bluuebunny/crossref_metadata_2025 huggingface dataset:
Current-Dependent Growth Mechanisms of Sodium Metal Anode in Diglyme-Based Electrolytes
Authors: Ma Bingyuan , Bai Peng
Published: February 2020

Sodium-ion batteries are economical substitute for lithium-ion batteries due to the earth abundance of sodium element [1, 2]. Similar to lithium metal anodes, while sodium metal anodes hold the promise to improve the energy density of next-generation sodium-ion batteries, the nonuniform electrodeposition of sodium metal that can lead to internal shorts remains a major obstacle toward its practical applications [3]. Here, we systematically investigated the electrodeposition of sodium in diglyme-based electrolytes in our unique capillary cells and realistic split cells. While a similar transition of electrodeposition mode to dendritic growth at Sand’s time was observed for sodium [4], only the smooth surface growths were observed at under-limiting current densities, suggesting a possible much higher cycling efficiency due to much less surface areas to be covered by the solid electrolyte interphase (SEI) layers. By examining the limiting current and Sand’s time obtained from operando experiments with the capillary cells, the diffusion coefficient (1.13×10-6 cm2 s-1) and transference number (0.45) of sodium ions in 1M NaClO4 in diglyme were accurately extracted, which were further verified by post-mortem analyses of linear sweep voltammetry experiments with split cells. The unique two current plateaus, shown in Figure 1, surprisingly can be explained by a single limiting current density in a self-consistent manner. At such plateaus, deposits of sodium metal were discovered to grow along the surface, rather than through the pores, of the ceramic-coated separator and form equiaxed and columnar dendrites with orthogonal branches similar to that found in solidification [5].Our work provides a platform to not only evaluate the current-dependent growth mechanisms of sodium, but also reveal the roles of separators toward designing safe sodium metal batteries.

References

[1] D. Larcher and J. M. Tarascon. Towards greener and more sustainable batteries for electrical energy storage. Nature Chemistry. 2015; 7(1): 19-29.

[2] M. D. Slater, D. Kim, E. Lee and C. S. Johnson. Sodium-Ion Batteries. Advanced Functional Materials. 2013; 23(8): 947-958.

[3] C. L. Zhao, Y. X. Lu, J. M. Yue, D. Pan, Y. R. Qi, Y. S. Hu, et al. Advanced Na metal anodes. Journal of Energy Chemistry. 2018; 27(6): 1584-1596.

[4] P. Bai, J. Li, F. R. Brushett and M. Z. Bazant. Transition of lithium growth mechanisms in liquid electrolytes. Energy & Environmental Science. 2016; 9(10): 3221-3229.

[5] L. Granasy, L. Ratkai, A. Szallas, B. Korbuly, G. I. Toth, L. Kornyei, et al. Phase-Field Modeling of Polycrystalline Solidification: From Needle Crystals to Spherulites-A Review. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science. 2014; 45A(4): 1694-1719.

Figure 1 Linear sweep voltammetry curve of the sodium symmetric split cell with twelve layers of ceramic coated separators with the ex-situ photos at different stages of the electrodeposition.

Figure 1
Hybrid Polymer Electrolytes for Lithium Metal Batteries
Authors: Wu Haiping , Liu Bin , Li Qiuyan , Zhang Linchao , Zhang Ji-Guang , Xu Wu
Published: February 2020

The use of lithium (Li) metal as anode in rechargeable batteries has been revived recently because Li metal has the potential to double the specific energy density of the state-of-the-art Li ion batteries. However, Li dendrite growth and low Coulombic efficiency still hinder the application of Li metal batteries. The urgent and most important thing is to develop an electrolyte which can enable Li metal to be used as anode with high safety and good stability. Solid polymer electrolytes (SPEs) have attracted much attention due to their outstanding advantages over conventional liquid electrolytes, including no leakage of electrolytes, good flexibility, low flammability, high safety and stable contact with the electrodes. As the most widely studied polymer in SPEs, polyethylene oxide (PEO) still faces some challenges, including the low ionic conductivity (σ < 10-5 S cm-1) at room temperature (RT) and instability when charged to above 4 V vs. Li/Li+.

In this work, we developed a hybrid polymer electrolyte (HPE) which exhibits high oxidation voltage and high ionic conductivity. The HPE shows an oxidation stability above 4.5 V vs. Li/Li+ when platinum was used as the working electrode in a three-electrode cell. The pure HPE has an ionic conductivity of 0.46 mS cm-1 and 2.8 mS cm-1 at 30 °C and 60 °C, respectively. The increased electrochemical window and the high conductivity of the HPE enable the Li||LiNi1/3Mn1/3Co1/3O2 cells (with an areal capacity loading of 2 mAh cm-2) to show a stable cycling in the voltage range of 3.0 – 4.2 V, having a high capacity retention of 84.2% after 170 cycles under charge rate of C/5 and discharge rate of C/3 at 60 °C. More details will be reported during the presentation at the meeting.

Acknowledgement

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, the Advanced Battery Materials Research (BMR) Program of the U.S. Department of Energy (DOE) under contract no. DE-AC02-05CH11231.
Electrochemical Properties of Assbs with High Energy Density Using Thin Solid Electrolyte Sheet
Authors: Ryu Hye-Min , Kim Da-Hye , Kim Min-Young , Jung Ha-Young , Ban Hee-Jung , Song Young-Woog , Jeon Se-Hyeon , Kim Ho-Sung
Published: February 2020

Recently, the use of liquid electrolytes in lithium batteries is prone to cause safety problems such as leakage and gas explosions. The PEO-based solid composite electrolytes (CE) for all-solid state batteries (ASSBs) have been studied for a possible replacement for liquid electrolytes. However, it results in degradation of mechanical properties and short circuit during cycling at the high temperature (60~80°C). Therefore, the thickness of electrolytes is required to be 150㎛ or more. However, to improve the energy density of all-solid state battery, it is required to reduce the thickness of the solid electrolyte layer to as low as 50㎛ and less. As a method for reducing the thickness, we suggested that the thin solid composite electrolyte film was composed of PEO/PVDF blending polymer as ionic conductor and binder including lithium salts and garnet LLZO powders. In addition, the composite cathode slurry was composed of NCM active material, Super P, Garnet-type LLZO powder and PEO/PVDF blending polymer. The electrochemical properties were measured by the AC impedance method, Linear Sweep Voltammetry, Symmetrical cell test and charge/discharge cell test. As a result, we will introduce the properties of CE with garnet LLZO powder, PEO and PVDF polymers in cathode and solid electrolyte layer. Finally, a pouch-type ASSBs having a bipolar structure in which energy density is improved by applying such a thin SE is described in more detail.
Facile Improvement of Dual-Functional Catalytic Activity of Perovskite La0.6Sr0.4CoO3-Δ Oxide Decorated with Nanostructured Palladium for Oxygen Electrochemical Reactions in Lithium-Air Battery
Authors: Nahm Kee Suk , Oh Mi Young , Lee Jon Ju
Published: February 2020

Perovskite La0.6Sr0.4CoO3-δ (LSC) and Ba0.5Sr0.5Co0.8Fe0.2O3-

δ (BSCF) oxides are still low in the catalytic activity of oxygen reduction reaction (ORR) although it exhibits relatively good catalytic activity for oxygen evolution reaction (OER) when using as oxygen electrode catalyst. To improve the ORR activity of the LSC, palladium (Pd) was deposited over the LSC surface with four different weight percent. The physicochemical properties of Pd decorated perovskite La0.6Sr0.4CoO3-δ (Pd/LSC) was studied by using various analytic techniques. It was observed that the palladium is deposited only on the surface of LSC powders in nanostructure forms with a stoichiometric composition, which gives no influence on the crystallinity of LSC. The surface area of the Pd/LSC samples increases with increasing the weight percentage of Pd and, over 10 wt%, dramatically increases due to the formation of Pd porous structure over the perovskite surface. The electrochemical characterization of the Pd/LSC was examined in both aqueous and non-aqueous electrolyte solutions. In aqueous electrolyte, the Pd/LSC materials exhibit higher ORR and OER activities than LSC and KB. The ORR activity rapidly increases with the increase of Pd wt% deposited in order of 5<10<20<30, while the OER activity displays not much different values for all the Pd weight percentages. The Pd/LSC materials were applied as air cathode catalyst of lithium air battery to examine their catalytic performances in non-aqueous electrolyte. The Pd/LSC materials exhibit higher catalytic activities in oxygen electrochemical reactions than LSC and KB. 30wt% Pd/LSC shows the highest discharge capacity and the longest cycle life. It is concluded that the decoration of Pd over perovskite LSC oxide is more effective to increase the ORR activity, resulting in increasing the performance of lithium air battery.
Investigation of the Effects of Crystallinity of Iron Oxyhydroxides on Na-Ion Charge Storage
Authors: Niu Sibo , Rhodes Christopher P.
Published: February 2020

Iron oxyhydroxides/oxides are potentially promising cathodes for room-temperature rechargeable sodium-ion (Na-ion) batteries due to their high natural abundance, low cost, and environmental benign properties. However, the large Na-ion radius and slow solid-state Na-ion diffusivity within iron oxyhydroxides typically results in low specific capacities, poor rate capabilities, and significant capacity degradation. In a number of metal oxide cathodes, materials with less ordered structures have improved electrochemical properties compared with highly crystallized structures. We have evaluated the effect of the degree of crystallinity of iron oxyhydroxides on their Na-ion charge storage properties. Iron oxyhydroxides/oxides with different degrees of crystallinity were prepared by altering the precursor concentrations and synthesis temperature during the hydrothermal synthesis process. The structure of the materials was characterized by powder X-ray diffraction, electron microscopy, thermogravimetric analysis, and vibrational spectroscopy. From our initial electrochemical analysis, less crystallized iron oxyhydroxide cathodes delivered higher reversible capacities, much better rate capabilities, and improved capacity retention upon cycling compared with more crystallized iron oxyhydroxides. The enhanced electrochemical performance of less crystallized iron oxyhydroxide cathodes could be attributed to facilitated Na-ion mobility, improved ability to accommodate reversible volume changes during ion insertion/de-insertion within the structure, and a higher degree of ion storage sites within the material. Understanding the important role of material crystallinity in Na-ion charge storage materials provides a promising way to develop high performance cathodes for Na-ion batteries.
Dual-Crosslinked Polyacrylamide Binders with Various Polysaccharides and Their Application to High Capacity Anodes
Authors: Gendensuren Bolormaa , Kim Jinyoung , Oh Eun-Suok
Published: February 2020

Over the last 20 years, much attention has been devoted to developing new electrode materials with high energy and power densities for lithium ion batteries (LIBs). However, a binder material providing an integrity in a composite electrode seems to have an attention recently due to its great influence on the long-term cyclic stability, rate capability, and irreversible capacity loss of the electrodes. High capacity anodes experiencing large volume change such as silicon is strongly dependent on proper choice of polymeric binder. Polyvinyledene difluoride (PVdF) is the most common binder in commercial LIBs. However, the Si electrode fabricated with PVdF binder showed rapid capacity fades for the first tens of cycles caused by the poor adhesion strength of PVdF on current collector. Moreover, it dissolves only in toxic and expensive organic solvent, m-methyl-2-pyrrolidone, leading to environmental issues for the electrode manufacturing process.

To replace the organic solvent, environmental-friendly water soluble polymers such as, polyacrylic acid (PAA), polyvinyl alcohol (PVA), carboxymethyl cellulose, and sodium-alginate (SA) began to be applied to high capacity Si-based anodes and showed excellent binder performance, when compared to conventional PVdF binder due to their robust adhesion to active material and current collector and low electrolyte swelling to maintain the mechanical properties of binder. In spite of these endeavors, further improvement in the binder materials is still required, especially for the use high capacity anodes to have sufficiently stable cyclic performance for commercial application.

In this presentation, water-treated dual-crosslinked binder systems will be introduced for a high capacity silicon/graphite electrode. A polysaccharide is first grafted with polyacrylamide (PAAm), and ionic and chemical crosslinkings are subsequently performed to complete dual-crosslinking in the grafted polymer. Three types of polysaccharides, sodium-alginate, sodium-carboxymethyl cellulose, and pectin, will be employed and compared for their performance as a binder material for high-capacity anodes. A variety of characterization tools will used to examine the electrochemical performance of the electrodes containing the dual-crosslinking binder systems.
Sulfurized Polyacrylonitrile Cathode and Polyacrylic Acid Binder for Advanced Potassium–Sulfur Batteries
Authors: Hwang Jang-Yeon , Kim Hee Min , Shin Subeom , Sun Yang-Kook
Published: February 2020

Room-temperature metal–sulfur batteries have attracted extensive interest because of their advantages of high theoretical capacity, high elemental abundance, and low cost.1 Towards improving the electrochemical performances of the sulfurized polyacrylonitrile (SPAN) composite cathode in potassium–sulfur batteries (KSBs),2-4 an advanced electrode design has been developed by applying a polyacrylic acid (PAA) binder to the SPAN electrode. By integrating the merit of the SPAN composite cathode and PAA binder, the proposed SPAN cell generates a high reversible capacity of 1,050 mA h g-1 and has excellent cycling stability after 100 cycles (95% retention of the initial cycle) at a high current density of 837.5 mA g-1.5 Ex situ Raman spectra show that the PAA binder is evidently more effective at improving the structural stability of the SPAN electrode than the PVdF binder during cycling. Despite the large volume changes during reduction/oxidation steps in the wide voltage window of 0.1–3.0 V, the SPAN electrode with the PAA binder gave an excellent electrochemical performance in KSBs. To better understand the electrochemical reaction mechanism of SPAN in KSBs, XPS analysis was further performed in a wide discharge cut-off voltage range.

References

B. Scrosati, J. Hassoun and Y.-K. Sun, Energy Environ. Sci., 2011, 4, 3287

J. Wang, J. Yang, J. Xie, and N. Xu, Adv. Mater., 2002, 14, 963

J.-Y. Hwang, H. M. Kim, C. S. Yoon and Y.-K. Sun, ACS Energy Lett.. 2018, 3
, 540

S. S. Zhang, Energies, 2014, 7, 4588

H. M. Kim, J.-Y. Hwang, D. Aurbach and Y.-K. Sun, J. Phys. Chem. Lett.. 2017, 8
, 5331
Solid-State Li-O2 Battery Using a Perovskite Type Solid Electrolyte with an Improved Interfacial Property
Authors: Khan Tamal T. , Park Chan-Jin
Published: February 2020

Theoretically Li–O2 batteries can release an energy density of 11 680 W h kg-1 comparable to that of gasoline (13 000 W h kg-1) by integrating the metal lithium with readily available ambient oxygen as an active material for cathode. Even based on the entire battery system, the capacity of ~1000 W h kg-1 is still several times higher than that of Li-ion batteries. Thus, Li–O2 batteries have attracted significant attention as a possible green alternative to current lithium-ion batteries for electric vehicles. Though Li-O2 batteries have promising performance, several issues still exist in its practical operation. One major issue is the use of liquid electrolytes, which causes several problems including evaporation, leakage, flammability, low oxygen solubility and diffusion, and chemical and/or electrochemical instabilities. The use of a solid-state electrolyte can be alleviated this issue. In addition, the solid-state electrolyte can significantly improve the stability of Li–O2 batteries for long-term operation by shielding the Li anode from oxygen, CO2, and moisture in the air. The solid-state electrolyte can also protect short circuiting caused by Li dendrites during long term operation.

In our study, we propose and fabricate a novel solid-state Li-O2 cell composed of a Li metal as an anode, Al2O3 as an interlayer, a perovskite-structured Al-doped Li-La-Ti-O (A-LLTO) as solid electrolyte, and a solid electrolyte integrated cathode frame covered with a carbon layer and CoO nanoparticles as catalysts for the cyclic oxygen evolution reaction and oxygen reduction reaction. In our research, we used ALD of Al2O3 as an interlayer due to its ability to prevent the direct contact between Li and A-LLTO solid electrolyte to enhance the stability of solid electrolyte against Li anode, and to form a thermodynamically stable Li ion conducting LiAlOx solid electrolyte by reacting with Li that will enhance the Li ion migration. This work demonstrates the importance of interface coupling between Li anode and solid electrolyte on the development of high performance Li−O2 batteries.
Fabrication of a Spinose Structure LiFePO4 Cathode Via Surface Etching to Improve the Rate Capability and Cycling Stability of Li-Ion Batteries
Authors: Kim Jiyong , Lim Taehoon , Martinez-Morales Alfredo A.
Published: February 2020

Lithium iron phosphate (LiFePO4, LFP) has been demonstrated as a suitable cathode material for Li-ion batteries due to its relatively high theoretical capacity (170 mAh·g-1), cost effectiveness, long cycle life, good thermal stability, and environmental friendliness, However, key limitations of LFP are its low intrinsic electronic conductivity (10-9-10-10 S·cm-1) and limited lithium ion diffusion channel (one-dimensional path along the b-axis of the olivine structure), leading to poor rate capabilities and cycling stability in LFP batteries. To improve the rate capability of LFP cathode, the low electronic conductivity can be resolved by conductive material coating, heteroatomic doping, and downsizing of active materials.

To improve the rate capability and cycling stability of LFP battery, we propose the surface treatment of LFP cathode material to increase the surface area. The surface area of LFP is controlled by the concentration of etching agents (0.5 M to 2.0 M), etching time (10 min to 360 min), and reaction temperatures (25 °C to 80 °C). The morphology of the etched LFP surface is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The specific surface area and crystal structure of surface etched LFP are characterized by Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD), respectively. To determine battery performance, coin-cells are assembled with cathodes containing various surface areas. Cycling testing is performed using an Arbin tester to measure the rate capability at different C-rates and cycling stability at same C-rate.
Si/C Composite As an Anode Material with Ultrafast Charging Capability for Lithium Ion Batteries
Authors: He Qianran , Ashuri Maziar , Liu Yuzi , Shaw Leon
Published: February 2020

We successfully synthesized a nitrogen-doped Si/C composite with nano-channels as an anode material, which shows high capacity, high power and long cycle life. According to our preliminary electrochemical results, the as-synthesized N doped-Si/C composite could deliver 1000 mAh/g of Si specific capacity at the current density of 6A/g over 500 charge/discharge cycles, and could live up to 1000 cycles under higher current density at 8A/g while still providing higher specific capacity than the state-of-the-art carbonaceous anodes. The facile method of synthesizing this high performance ultrafast charging N-doped Si/C composite can broaden the application areas of Si anodes in portable devices and electrical vehicles. Characterizations of the material and its electrochemical properties will be presented. In particularly, SEI layer formation and evolution under long term cycling along with cell impedance alternation will be discussed to elucidate the ultrafast charging and long cycle life mechanisms.
Interdigitated Eutectic Alloy Anodes with High-Volumetric Capacity for Lithium-Ion Batteries
Authors: Heligman Brian T , Kreder Karl J , Scanlan Kevin P , Sun Ruojiao , Manthiram Arumugam
Published: February 2020

Interdigitated eutectic alloy (IdEA) foils are highly promising anodes for lithium-ion batteries. The framework appears commercially promising across a variety of metrics; electrode-level volumetric capacity is approximately double that of graphite (798 mA h cm-3
), the lithium plating risk is eliminated, formation losses are below < 10%, and coulombic efficiency has reached ~ 99%. Synthesized via severe plastic deformation, a two-phase alloy is converted into a nanostructured foil composed of alloying domains distributed throughout an electrically conductive matrix. The scalable approach uses abundant materials and requires no slurry-coating or drying, potentially eliminating ~ 80% of electrode processing costs. However, the electrochemistry of the system is more complex than would be expected for a simple mixture of the constituent phases. In our Zn-Sn embodiment, long-term degradation was closely correlated with the cycling of a previously unobserved non-equilibrium ternary phase. Given the potential of a nascent system for record volumetric capacity (1,084 mA h cm-3) and the broad class of viable IdEA systems, further study is merited, and continued exploration of the IdEA framework may unlock unmatched next-generation anodes.

Figure 1
Insights into the Phase Transformation and Degradation Mechanisms of Al and Al-Alloys for Lithium-Ion Battery Anodes
Authors: Tahmasebi Mohammad Hossein , Kramer Dominik , Zheng Tianye , Mönig Reiner , Boles Steven T.
Published: February 2020

Despite the tremendous progress made towards understanding the alloying and dealloying mechanisms in new lithium-ion battery anode materials like silicon and tin, the large volumetric changes that are intrinsic to these materials seem difficult to overcome in the absence of additional coating or nano-structuring methods that inherently increase cost and decrease capacity. Thus, the most likely candidate to replace graphite in the future may not be that which has the absolute highest capacity, but one that has an optimal balance between cost, capacity and processing complexity. Aluminum has significant advantages over other alloy anodes because of its low cost, high abundance, and wide variety of film and foil processing options. If the high theoretical capacity of aluminum (ca. 1 Ah/g or 2.7 Ah/cm3) can be even partially realized, it would be a significant improvement over conventional carbon-based anode materials. Despite the great promise of aluminum as an anode material in lithium-ion batteries, it typically suffers from fast capacity fading upon cycling. Unfortunately, the depth of knowledge concerning the degradation mechanisms of aluminum-based anode electrodes is still scarce.

In this work, aluminum and aluminum-based alloys are used to investigate the lithiation, delithiation, and degradation mechanisms in this industrially-friendly materials system. Various in situ and ex situ microscopy methods are employed, along with conventional electrochemical cycling and characterization techniques, to investigate the phase transformations associated with the Al-Li system, in particular from the α-phase (Al) to the β-phase (AlLi), during charging and discharging. Furthermore, substrate curvature methods are used which allow for quantitative insights into the mechanical properties of the film as a function of lithium content. Scanning electron microscopy investigations of the surface morphological evolution of the aluminum-based thin-film electrodes indicate that irreversible damage depends more on the depth of discharge than on the volume contraction during delithiation [1]. These results suggest that aluminum-based anodes may be highly suitable for future lithium-ion battery anodes and implications for commercially available aluminum foils as anode materials will be discussed.

[1] M. H. Tahmasebi, D. Kramer, R. Mönig, and S. T. Boles, “Insights into Phase Transformations and Degradation Mechanisms in Aluminum Anodes for Lithium-Ion Batteries,” J. Electrochem. Soc., vol. 166, no. 3, pp. A5001–A5007, 2019.
Intercalating Solid State Electrolyte Based Composite Electrode for Lithium-Sulfur Batteries
Authors: Irshad Ahamed , Elizalde-Segovia Rodrigo , Jayathilake Buddhinie Srimali , Moy Derek , Plichta Edward J. , Hendrickson Mary A. , Narayanan S. R.
Published: February 2020

There is a necessity for extending the cycle life and rate capability on lithium-sulfur (Li-S) batteries. Prevention of the polysulfide shuttle, suppression of the lithium dendrite formation, and construction of an efficient electrode architecture are the main challenges in advancing Li-S battery technology 1.

In the present work, we introduce an intercalating solid state electrolyte (ISSE) made of nanoparticles of lithium cobalt oxide (LCO). The ISSE is combined with the sulfur to form a composite electrode to enhance the cathode architecture suitable for supporting a high sulfur loading in Li-S electrodes. In addition, we present the improved performance of the ISSE composite cathode with our nonporous mixed conduction membrane (MCM) made of LCO and polymer electrolytes. The feasibility of this concept is shown the discharge and charge curves plot (Fig 1).

In our past studies MCM was found to be effective in suppressing the polysulfide shuttle and therefore provides high capacity retention and extension of the cycle life 2. The MCM layer can be fabricated as thin as 20 microns when prepared using a sacrificial aluminum substrate. We also demonstrate a technique to prepare crack-free sulfur electrodes with different types of carbons. The introduction of ISSE and the implementation on the crack free cathode side reduces or eliminates the necessity of a liquid electrolyte, allowing the diffusion of ions by taking advantage of the intercalation mechanism, this opens the possibility of extending the performance of Li-S to reasonable charge and discharge rates in a solid or hybrid solid-liquid electrolyte configuration.

References

(1) Fan, X.; Sun, W.; Meng, F.; Xing, A.; Liu, J. Green Energy Environ.
2018, 3 (1), 2–19.

(2) Moy, D.; Narayanan, S. R. J. Electrochem. Soc.
2017, 164 (4), A560–A566.

Figure 1
Nanocarbon Composites for Energy Storage Applications
Authors: Ci Lijie
Published: February 2020

In my talk, I will introduce our recent work on energy storage nanocarbon composite materials. Several structural designs of graphene and nano silicon anode composites were prepared for high energy density lithium ion battery; We also produced double-shell of graphene and artificial solid state electrolytes, such as Li7P3S11(LPS), Li4SiO4, LiAlO2, encapsulated commercial Si nanoparticles structure for LIB anode with excellent cycling stability and superior rate capability. A simple ball milling method was found to be a suitable method to produce nano-sized LiMn2O4and nanocarbon (graphene, carbon nanotubes, or super P) composites for high performance hybrid supercapacitor application. I will also introduce our work using porous nanocarbons as Li host materials for Lithium metal battery application.

Ref:

Ai Q., Ci L., et al., Diamond and Related Materials 88, 60 (2018)

Chen L., Ci L., et al., Journal of Power Sources 392, 116 (2018)

Xu X., Ci L., et al., Electrochimica Acta 276, 325 (2018)

Hou G., Ci L., et al., Journal of Power Sources 386,77 (2018)

Ma X., Ci L., et al., Journal of Materials Chemistry A 6, 1574 (2018)

Ma X., Ci L., et al., Scientific Reports 7, 9642 (2017)

Zhai W., Ci L., et al., Nano Research 10, 4274 (2017)

Feng J., Ci L., et al., Journal of Power Sources 287, 177 (2015)
Visualization of Anti-Pulverization of Nickel Sulfide in Hierarchical Carbons Shells
Authors: Park Jae Hyun , Lee Jae W.
Published: February 2020

Nickel sulfide (NiS) has attracted attention as an anode material for lithium ion batteries due to its high theoretical capacity (590 mAh g-1), high thermal stability and low resistance compared to traditional metal oxides. However, the main problem of this NiS was a pulverization of the electrode after some cycles, and hence it was electrochemically isolated. In this study, the mixture of NiS and CaCO3 nanoparticles were coated with carbon by toluene CVD. As a result, the carbon shell layer with a hierarchical structure was formed around NiS, and the resultant material had a superior capacity of 575 mAh g-1 at 0.1 A g-1 for the anode material of lithium ion battery. In long-term cycle test, nickel sulfide was pulverized, but resultant pieces were preserved by the coated carbon shell during 100th cycle. However, after 100th cycles, the pulverization occurred continuously, and NiS was separated into metallic nickel and lithium sulfide. This lithium sulfide converted into polysulfides that have high solubility and mobility in the electrolyte, and the polysulfides eventually escaped out of the carbon shell. As a result, the capacity increased up to 606 mAh g-1 until 97th cycle, and then it decreased to 483 mAh g-1 at 200th cycle. This phenomenon was observed by the visualization of cycle-by-cycle TEM images and confirmed using additional ex situ analyses.
Surface Modifications on LiCoO2-Based Cathodes for High-Density Lithium-Ion Batteries with Long Cycle Life
Authors: Feng Zhenxing , Holstun Tucker
Published: February 2020

Commercial rechargeable lithium-ion batteries (LIBs) use LiCoO2(LCO) as the cathode, which shows relatively low energy capacity (~140 mAh/g) and suffers poor cycle life performance. To develop next-generation LIBs with high voltage, high capacity and long cycle life, surface modifications on cathodes have been applied. We start with thin layers of Li2SrSiO4(LSSO) synthesized from sol-gel method to coat on the LCO surfaces and to test the optimal conditions, namely thickness and annealing temperature, for LIB performances in both half-cell and full cell configurations. LSSO is predicted by theoretical calculation1as the best surface coating but our results show that LSSO alone cannot lead to improved performance at 4.5 V cut-off voltage but a combination of LSSO and Al2O3could yield the best protection and performance. Following a series of electrochemical tests, electron microscopy and synchrotron X-ray characterizations, we provide some insights about mechanism in our surface modification.

[1] M. Aykol et al., Nature Communications, 7, 2016, 13779
Structural and Electrochemical Insights into Iron-Based Fluoro(hydroxy)Phosphate axFePO4y (A= Na, Li; Y= F, OH) As Cathode Materials for Aqueous Batteries
Authors: Sharma Lalit , Okada Shigeto , Barpanda Prabeer
Published: February 2020

In search for efficient cathode materials for batteries, the focus has shifted from oxides to Polyanion based materials. Polyanions not only impart thermal and structural stability to the material but also enhance the electronegativity of the central atom which in turn increases the voltage of the material. Hence, a lot of research has been done on PO4-based materials especially when combined with other anions like F- or OH-. However, safety and cost of existing organic electrolytes force us to revisit the possible application of aqueous electrolytes. Use of aqueous electrolytes reduces the toxicity and increases the ionic conductivity by two-fold. The limited working potential range of aqueous electrolytes to avoid water splitting makes it important to look for efficient and stable electrode materials. In this pursuit, we present two case studies using earth-abundant Fe-based compounds. First, Na2FePO4F is demonstrated as a cathode material for aqueous sodium-ion batteries. A discharge capacity of 85 mAh g-1 at 1 mA cm-2 current density with excellent rate kinetics was observed for half-cell configurations. [Figure 1(a)] A full cell was assembled with NaTi2(PO4)3 anode and the Na2FePO4F | NaTi2(PO4)3 full cell delivered a reversible capacity of 85 mAh g-1 working as a 0.8 V battery (ChemElectroChem, In Press, 2018). The second work is based on LiFePO4OH which works as an anode for aqueous lithium-ion batteries (LIBs). It is reported as a 2.5 V battery cathode material for LIBs in organic electrolytes. However, it was found to be working in the anodic range for aqueous batteries. In half-cell configuration, it delivered a discharge capacity of 153 mAh g-1 with very good rate kinetics. [Figure 1(b)] A full cell was assembled with LiFePO4 as a cathode and an energy density of 70 Wh kg-1 was observed in the first cycle. The structural characterization along with electrochemical studies will be showcased for both case studies.

Figure 1: Galvanostatic (dis)charge profiles and cyclability of (a) Na2FePO4F, (b) LiFePO4OH in aqueous electrolytes in half-cell configuration.

Figure 1
(Invited) Elucidating Interfacial Phenomena in Li-Metal Based Batteries
Authors: Balbuena Perla B.
Published: February 2020

The success of advanced “beyond Li-ion” batteries is highly dependent on controlling important issues associated with the reactivity of the Li metal anode but also those derived from the controlling the cross talk events between anode and cathode. In this talk, we will discuss both topics. First, we address the reactivity of the Li metal anode. In particular we will report our recent progress related to Li metal deposition and the role of the electrolyte composition, solid electrolyte interphase (SEI) formation and stability. We evaluate both liquid and solid electrolytes and discuss details associated with the electronic structure of the nucleated structures and the SEI fragments formed at their surfaces at several potentials. We characterize using various levels of modeling the evolution of such structures and their interplay and effects on macroscopic variables. We then address cathode reactivity, formation of cathode electrolyte interphases, and the effect of metal dissolution on the anode SEI.
(Invited) Area Selective Atomic Layer Deposition As an Emerging Process for Advanced Nanofabrication
Authors: Bobb-Semple Dara , Liu Tzu-Ling , Bent Stacey F.
Published: February 2020

The rapid growth of technologies such as artificial intelligence and autonomous vehicles is fueling a need for more powerful electronic chips, which the semiconductor industry is working to meet with ever-more complex nanoscale device structures. With this growing need for nanostructure fabrication, selective deposition is gaining much attention as an important process to achieve pattern features at the ~10 nm length scale. Both two-dimensional planar geometries and three-dimensional structures will benefit from selective deposition processes, with bottom-up growth strategies providing advantages in reduced process complexity and improved pattern fidelity. In this presentation, we will describe how control over surface chemistry using molecular monolayers can achieve area selective atomic layer deposition (ALD). ALD is a good choice for selective deposition because its chemical specificity provides a means to achieve selectivity on a spatially patterned substrate. In particular, inhibitory layers such as self-assembled monolayers (SAMs) can alter the native surface reactivity, allowing ALD selectivity to be achieved. We will show that this process provides good selectivity for thin deposited films, and demonstrate selective deposition on different materials, including dielectrics and metals such as Cu, Co, W and Ru. Because area selective ALD processes often break down after more than a few nanometers of material is deposited, strategies to overcome the undesired ALD nucleation on the inhibitory layer and achieve significantly higher selectivity in area selective ALD are also important. Two such strategies that improve the final selectivity will be described, including SAM repair between ALD cycles and a self-correcting process in which selective deposition is combined with selective etching. With both approaches, selective ALD of more than 60 nm of metal oxide dielectric material can be achieved. Directions toward new area selective deposition processes will also be described.
Evaluating the Intrinsic Material Stability at the Semiconductor/Electrolyte Interface for Solar Fuel Production
Authors: Yu Weilai , Lewis Nathan S
Published: February 2020

Stability is one of the most critical issues that determines the material selection for components used in integrated solar fuel generators. Although a variety of III-V semiconducting compounds with suitable band gaps can be used in tandem solar-cell devices, their material robustness in acidic/alkaline electrolyte under solar-driven water-splitting/solar-free dark conditions remains ambiguous. Thus, it is urgent and useful to evaluate whether these material have serious corrosion issues and whether their corrosion can be mitigated via mechanistic understanding. Herein, in a rigorous manner, we present a comprehensive study to understand the fundamental corrosion chemistry of these technologically-important semiconductors. Various characterization techniques including inductively coupled plasma mass spectroscopy (ICP-MS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and atomic-force microscopy (AFM) are combined to directly reveal the physical/chemical transformations occurring at the semiconductor/electrolyte interface. Combined with considerations of thermodynamic pourbaix diagrams, their sophisticated corrosion behaviors can be understood under varying conditions. Eventually, rational protection strategies are proposed to realize prolonged lifetime for sustained and practical solar fuel generation.
Oxides of Manganese As Efficient Bifunctional Electrocatalysts
Authors: Roy Indroneil , Wang Qi , Chakrapani Vidhya
Published: February 2020

The electrolysis of water, or water splitting reaction is one of the cleanest ways of producing hydrogen and oxygen gas for fuel. Electrochemical devices employing these reactions include regenerative fuel cells and rechargeable metal-air batteries, which have the highest theoretical energy density. Considerable efforts have been dedicated towards improving the energy conversion efficiency of these devices. However, the single main obstacle for achieving this has been the lack of suitable bifunctional oxygen electrocatalysts that show simultaneous high activity for both oxygen reduction (ORR) and oxygen evolution (OER) reactions during charge/discharge cycles. The overpotential and slow kinetics of oxygen reactions are limiting parameters in the advancement of electrochemical storage devices. Taking inspiration from nature’s photosynthetic process that uses a Mn4O4Ca cluster in photosystem II to catalyze water splitting, we studied the efficiency of various phases of manganese oxide (MnOx) as electrocatalysts for OER and ORR process, including the role of defects on bifunctionality. Cyclic voltammetry was used to prove that Mn2O3 is a bifunctional catalyst by showing high activity for OER and ORR. Next, in-situ UV-Vis absorbance spectroscopy was conducted to track changes in the surface oxidation state as a result of occurring reactions. Finally, we use electrochemical quartz crystal microbalance to track ion intercalation into the material. Results from these studies were used to obtain a structure-defect-function correlation that can improve the design of electrocatalysts with bifunctional properties.

Acknowledgements: The authors would like to thank Rensselaer Polytechnic Institute (RPI) and National Science Foundation, CBET award (No: 1511733), for the partial financial support and Nicholas Smieszek for his assistance with the preparation of this manuscript. I.R, and Q.W also gratefully acknowledge the partial support of Howard P. Isermann fellowship provided by the Department of Chemical and Biological Engineering at RPI.
(Invited) Morphological Engineering for Polymer-Based Electrochemical Sensors
Authors: Kim Chang-Hyun
Published: February 2020

Bioelectronic devices incorporating polymeric materials into their active region has recently emerged as a driver for the next-generation sensors and healthcare technologies. A rapidly growing interest in this new application of versatile organic semiconductors and conducting polymers has been witnessed during the last few years, shaping a distinct field of ‘organic (or plastic) bioelectronics’. Low-temperature, large-area processability (e.g. printing), excellent biocompatibility, chemical tunability, and mechanical softness are some of the major reasons that organic-based bioelectronics can be a promising option for unconventional wearable and implantable platforms. However, only a small number of materials have shown promising performances up to now, and the systematic understanding has been lacking on the general processing-structure-property relationships of relevant polymers. In this presentation, a facile solution-based post-deposition morphological modification technique is reported, which successfully applied to the model bioelectronic polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Besides the intended solid-state structural transformation, a multitude of beneficial effects on the performances of electrochemical transistor devices (a fundamental sensing element in bioelectronics) made of the engineered materials were clearly observed and systematically analyzed by a number of experimental tools. Most importantly, the nanoscale chain re-arrangements and induced long-range crystallinity gave rise to the substantial compositional changes that eventually led to the improved anti-swelling property, larger volumetric capacitance, and unprecedentedly high thermal and environmental stability. It is therefore expected that both the scientific understanding and application potentials underlined in this study will serve as a practical guideline for the development of viable organic bioelectronics technologies.
(Invited) Laser Printed Organic Field-Effect Transistors on Paper
Authors: Jurchescu Oana D
Published: February 2020

Laser printing is a low-cost, environmentally friendly and high-throughput technique that is compatible with flexible substrates. This coating method is ubiquitous in many areas, but, in spite of its clear advantages, it has not been adopted for manufacturing electronic devices. In this presentation, I will introduce the use of laser printing for deposition and patterning of organic thin-film transistors. This solvent-free processing method allowed for simultaneous deposition, purification, and patterning of the organic semiconductor layer and definition of contacts in transistors realized on flexible substrates such as plastic and paper. We performed electrical characterization of the devices and related the results with the structural features extracted from grazing incidence wide angle x-ray scattering. To define the electrodes, we used aerosol spray laser lithography in conjunction with different metal inks; the pattern was created using a regular toner, which was subsequently selectively removed. We created a grid of transistor devices with variable channel lengths and widths, and obtained good charge carrier mobilities and an excellent tolerance to extreme bending. The success of this method marks an opportunity for a rapid, scalable, environmental friendly and low-cost alternative to current manufacturing techniques for development of flexible, large-area, electronic applications.
(Invited) Growth and Characterization of GaN Based Multi-Channel FETs
Authors: Xie Andy , Beam Edward , Cao Yu
Published: February 2020

With recent advances in new device architectures such as FIN FETs, Super-Lattice Castellated Field Effect Transistors (SLCFET), and buried dual gate FETs (BRIDGE FET), there is more and more advantages for GaN based multiple channel FETs. By simply increasing the number of channels, the Ns can be increased to several times higher than a single channel device. However, the maximum number of the channels is largely limited by the tensile stress in the AlGaN/GaN materials system. By optimizing the growth conditions and delta doping, we have achieved a sheet resistance as low as 21 Ohm/sq in a 16-channel FET structure. We also found that, by controlling the delta doping, the sheet resistance is linearly scaled with the number of channels.
(Invited) Detection of Heart Failure-Related Biomarker in Whole Blood with Graphene Field Effect Transistor Biosensor
Authors: Zhang Guojun
Published: February 2020

Since brain natriuretic peptide (BNP) has become internationally recognized biomarkers in the diagnosis and prognosis of heart failure (HF), it is highly desirable to search for a novel sensing tool for detecting the patient’s BNP level at the early stage. Here we report a platinum nanoparticles (PtNPs)-decorated reduced graphene oxide (rGO) field effect transistor (FET) biosensor coupled with a microfilter system for label-free and highly sensitive detection of BNP in whole blood. The PtNPs-decorated rGO FET sensor was obtained by drop-casting rGO onto the pre-fabricated FET chip and subsequently assembling PtNPs on the graphene surface. After anti-BNP was bound to the PtNPs surface, BNP was successfully detected by the anti-BNP immobilized FET biosensor. It was found that the developed FET biosensor was able to achieve a low detection limitation of 100 fM. Moreover, BNP was successfully detected in human whole blood sample treated by a custom-made microfilter, suggesting the sensor’s capability of working in a complex sample matrix. The developed FET biosensor provides a new sensing platform for protein detection, showing its potential applications in clinic sample.
(Invited) Interactive Skin Display with Epidermal Stimuli Electrode
Authors: Park Cheolmin
Published: February 2020

In addition to the demand for stimuli-responsive sensors that can detect various vital signals in epidermal skin, the development of electronic skin displays that quantitatively detect and visualize various epidermal stimuli such as the temperature, sweat gland activity, and conductance simultaneously are of significant interest for emerging human-interactive electronics used in health-monitoring [1,2]. First of all, shape-deformable and self-healing EL displays (SSELD) are presented. Light emitting materials are fabricated by adding a certain amount of a plasticizer to elastomer containing light-emitting phosphors to obtain a viscoelastic composite that undergoes facile shape-deformation and recovery. A capacitive SSELD exhibits frequency-dependent field-induced light emission under alternating current (AC). A SSELD self-recovers its EL within few minutes of electrical failure with more than 100 cycles of failure-recovery operation endurance. By combining with a shape-deformable ionic liquid, a novel fiber display which exhibits excellent shape-deformable and self-healing EL performance. Second, a novel interactive skin display with epidermal stimuli electrode (ISDEE) is demonstrated, allowing for the simultaneous sensing and display of multiple epidermal stimuli on a single device. It is based on a simple two-layer architecture on a topographically patterned elastomeric polymer composite with light-emitting inorganic phosphors, upon which two electrodes are placed with a certain parallel gap. The ISDEE is directly mounted on human skin, which by itself serves as a field-responsive floating electrode of the display operating under AC. The AC field exerted on the epidermal skin layer depends on the conductance of the skin, which can be modulated based on a variety of physiological skin factors, such as the temperature, sweat gland activity, and pressure. Conductance-dependent field-induced electroluminescence is achieved, giving rise to an on-hand sensing display platform where we can directly sense and visualize a variety of human information.

References:

[1] J. H. Lee, C. Park et al. Adv. Funct. Mater. 26, 5391 (2016)

[2] E. H. Kim, C. Park et al. Nat. Comm. 8, 14964 (2017)