bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Chemical Modification of Si Nanoparticles for Application in Si-Based Anode
Authors: Jiang Sisi , Hu Bin , Tornheim Adam , Zhang Lu , Zhao Bin , Zhang Zhengcheng 
Published: February 2020

Silicon (Si), with its extremely high theoretical specific capacity (up to 4200 mAhg−1), natural abundance and low toxicity, is considered as one of the most promising anode material candidates for next generation high energy density lithium-ion batteries. However, large volume expansion (~300 %) upon lithiation/delithiation makes it difficult for Si-based anode to maintain its capacity over extended cycles. Several possible mechanisms have been proposed to explain the rapid capacity fade in Si-based anode such as pulverization of the active materials, loss of electrical pathways caused by rearrangement of electrode structure, instability of the electrode/electrolyte interface or some combinations of these. While application of nano-structured Si (nanoparticles, nanowires) as anode largely resolved the pulverization issue, the use of nano-silicon inevitably increases the reactive surface between active materials and the electrolyte. Additionally, the continuous growth of solid-electrolyte-interphase (SEI) on the particle surface remains a significant cause for performance deterioration. Therefore, an increasing number of research has focused on the correlation between surface functionality of Si NPs and their electrochemical performance. Previous studies in this area mainly focused on the study of the inherent SiOx layers on Si NPs or the effect of electrolyte additives on the surface properties of Si NPs.
We take a different strategy to address the Si anode issue. We propose to chemically modify the surface of Si NPs and study how the chemical modification would affect the electrochemical performance of the Si-based anode. Commercially available Si NPs usually bear a native layer of silicon oxide on the surface of the particle. The first step in the surface modification of Si NPs is to enrich the surface silanol (Si-OH) groups as the new working platform. The silanol enriched surfaces will be converted to a variety of functional groups on the Si NPs. (Scheme 1). In this paper, we will present some preliminary results on the surface-modified Si NPs with methacrylate group and amine group and discuss the effects of the functional groups on the electrochemical performance of the Si anode.

Scheme 1. Chemical surface modification of Si NPs via silane chemistry.

Figure 1
Fabrication of Li-Polymer/Silica Aerogel Nanocomposite Electrolyte for an All-Solid-State Lithium Battery
Authors: Lim Ye Sol , Yoon Mi Young , Hwang Hae Jin 
Published: February 2020

The demand for solid-state lithium ion electrolytes has increased owing to the safety concerns regarding the use of lithium ion batteries, which contain flammable organic solvent electrolytes. The liquid electrolyte can give rise to serious problems such as leakage and gas explosions when the operating temperature rises. The use of an organic or inorganic solid electrolyte not only results in improved safety, but also facilitates the fabrication of miniature batteries using thin films.
A solid electrolyte is required to have high lithium ion conductivity, mechanical strength, and transference number for lithium ions as well as good thermal/electrochemical stability and compatibility with the electrodes. Recently, polymer-based solid electrolytes have been widely studied for a possible replacement for liquid electrolytes. Various types of polymer-based solid electrolytes for lithium ion batteries exist, such as polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and polyvinylidene fluoride (PVDF). Among them, the PEO-based polymer has attracted considerable attention, owing to its flexible skeleton and good interfacial stability with lithium electrodes. The mechanism of lithium ion conduction in the PEO-based solid-polymer electrolyte involves the coordination of the lithium ion from the Li-salt by the ether oxygen from the PEO, which moves according to the polymer segmental motion.
In this study, a polymer blend of PEO and PVDF, containing fluorine as a polar element, was fabricated to improve the dissociation degree of the Li-salt. In addition, we anticipate that the addition of ultra-porous silica aerogels, which has a high porosity and specific surface area, would increase the lithium ion conductivity. The silica aerogel was fabricated from water glass using the emulsion polymerization method, as was previously described by our research group. We also investigated the effects of the PEO:PVDF molar ratio, polymer:Li-salt molar ratio, and silica aerogel content on the structural, thermal, and electrical properties.
Zn/MnO2 Battery Chemistry with H+ and Zn2+ Co-Insertion
Authors: Sun Wei , Wang Fei , Wang Chunsheng 
Published: February 2020

Rechargeable aqueous Zn/MnO2 battery chemistry in a neutral or mildly acidic electrolyte has attracted extensive attention recently because all the components (anode, cathode, and electrolyte) in a Zn/MnO2 battery are safe, abundant, and sustainable. However, the reaction mechanism of the MnO2 cathode remains a topic of discussion. Herein, we design a highly reversible aqueous Zn/MnO2 battery where the binder-free MnO2 cathode was fabricated by in-situ electrodeposition of MnO2 on carbon fiber paper in mild acidic ZnSO4+MnSO4 electrolyte. Electrochemical and structural analysis identify that the MnO2 cathode experience a consequent H+ and Zn2+ insertion/extraction process with high reversibility and cycling stability. To our best knowledge, it is the first report on rechargeable aqueous batteries with a consequent ion-insertion reaction mechanism.
In this study, we demonstrated that the electrodeposited MnO2 experienced the successive H+ and Zn2+ insertion processes with a distinct difference in reaction kinetics during the discharging. The electrodeposited MnO2 has a nanocrystalline structure, in which the particle size is typically less than 10 nm, providing abundant electrode/electrolyte contact interfaces and reduced ion diffusion path and ensuring that the reaction with slow electrochemical kinetics could also happen. The as-designed Zn/MnO2 battery delivered an excellent cycling performance with a low capacity decay rate of 0.007% per cycle for 10,000 cycles at a high rate of 6.5 C.

Figure 1
Highly Stable Triclinic Polymorph in Nanoscale Na2-2xCo1+XP2O7/C for High-Voltage Na-Ion Battery Cathode
Authors: Song Hee Jo , Kim Jae-Chan , Kim Dong-Wan 
Published: February 2020

In Na-ion batteries (NIBs), the net energy density decreases because of the intrinsically low practical capacity and limited Na ion migration compared to that of Li-ion batteries (LIB). So, it is essential to use a high-voltage cathode to compensate these problems [1]. Pyrophosphates are one of the candidates that can be used as high-voltage cathodes [2]. In pyrophosphate-based materials, it is well-known that the operating voltage can be increased if the transition metals (TMs) such as Mn, Co, or Ni are used instead of Fe under electrochemical TM2+
/TM3+ redox reactions [3,4]. Particularly, Na2CoP2O7 with triclinic polymorph exhibits an average operating voltage of ~4.3 V (vs. Na/Na+), which is one of the NIB cathode materials that electrochemically react with Na ions at high-voltage ranges [5]. Unfortunately, however, it is hard to synthesize a pure triclinic polymorph because of its metastability in synthesizing process. So, preparing a highly stable and pure triclinic-polymorph Na2CoP2O7 is challenging work for high-voltage cathode in NIBs.
In this work, we analyze an appropriate elemental ratio of Na/Co in Na2-2xCo1+xP2O7 to prepare a stable triclinic polymorph, and determine suitable synthetic conditions in each bulk and nano compound. The formation of rose or blue phase Na2CoP2O7 with regard to their particle size is schematically illustrated in Fig. 1. Also, the electrochemical performance is measured for the high-voltage NIB cathode. Na1.8Co1.1P2O7 nanoparticles with C (Na1.8Co1.1P2O7-NPs/C) exhibited the discharge capacity of 90 mA h g-1 at the 30th cycle. High operating voltage and good specific capacity could lead to the significant increase in energy density to ~400 Wh kg-1, which is the highest value among polyanionic NIB cathode materials.

Fig. 1. Schematic illustration for the formation of rose or blue phase Na2CoP2O7 with regard to their particle size.

References

[1] V. Palomares, P. Serras, I. Villaluenga, K. B. Hueso, J. Carretero-González, T. Rojo, Energy Environ. Sci. 5 (2012) 5884-5901.
[2] P. Barpanda, S.-i. Nishimura, A. Yamada, Adv. Energy Mater. 2 (2012) 841-859.
[3] G. Hautier, A. Jain, S. P. Ong, B. Kang, C. Moore, R. Doe, G. Ceder, Chem. Mater. 23 (2011) 3495-3508.
[4] M. Tamaru, S. C. Chung, D. Shimizu, S.-i. Nishimura, A. Yamada, Chem. Mater. 25 (2013) 2538-2543.
[5] H. Kim, C. S. Park, J. W. Choi, Y. Jung, Angew. Chem. Int. Ed. 55 (2016) 6662-6666.

Figure 1
Hierarchical Porous Carbon Spheres As an Effective Air Electrode for Li-O2 Batteries
Authors: Jeong Min-Gi , Jung Hun-Gi 
Published: February 2020

For years, lithium oxygen (Li-O2) battery has been attracted attention thanks to extremely high energy density which might substitute natural resource [1-3]. However, several issues have obstructed the practical application of Li–O2 batteries such as poor rate capability, low energy efficiency and short cycle life [4-6]. To overcome those drawbacks, herein we propose a novel approach for preparing multi porous hierarchal (micro-, meso-, and macro-) carbon as an efficient positive electrode for Li-O2 batteries. Unlike currently existing carbon material, the hierarchical porous carbon spheres have the integrity to accelerate O2 gas flowing and electrolyte circulation (Li+ and O2-), and to provide enough space for Li2O2 accumulation and O2/Li2O2 transformation. As-synthesized cathode delivered higher discharge capacity (3891 mAh g-1
c) than that of Super P cathode (2427 mAh g-1
c) in deep charge/discharge condition and guided to a high round trip efficiency (~70%) compared to that of carbon black (Super P) (~63%), and efficiently boosted the overall electrochemical performance of the Li–O2 batteries.
Furthermore, ruthenium (Ru) nanoparticles were uniformly dispersed inside the hierarchical architecture to increase the cathode surface adsorption energy toward O2 and decrease the over potential further, thus get benefit from the greater energy efficiency. Ru inclusion in our multi porous hierarchal carbon electrode (Triple hierarchical porous carbon spheres, THPC) effectively modified the morphology of discharge product (Li2O2) to a uniform toroidal-shaped, which is renowned for advancing the OER performance. Certainly, appreciation goes to the unique multi-porous structure of THPC cathode which offered a large number of active sites and allowed a uniform distribution Ru catalyst, thus facilitated a high capacity with prolonged cycle life alongside high energy efficiency.

References

[1] K. M. Abraham, Z. Jiang, J. Electrochem. Soc. 1996, 143, 1.
[2] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J.-M. Tarascon, Nature Mater. 2012, 11, 19.
[3] Z. Peng, S. A. Freunberger, Y. Chen, P. G. Bruce, Science 2012, 337, 563.
[4] B. McCloskey, D. Bethune, R. Shelby, T. Mori, R. Scheffler, A. Speidel, M. Sherwood, A. Luntz, J. Phys. Chem. Lett. 2012, 3, 3043.
[5] B. McCloskey, A. Speidel, R. Scheffler, D. Miller, V. Viswanathan, J. Hummelshøj, J. Nørskov, A. Luntz, J. Phys. Chem. Lett. 2012, 3, 997.
[6] J.-L. Shui, N. K. Karan, M. Balasubramanian, S.-Y. Li, D.-J. Liu, J. Am. Chem. Soc. 2012, 134, 16654.
Comparative Study Nickel Rich Layered Oxides: NMC 622, NMC 811 and NCA Cathode Materials for Lithium Ion Battery
Authors: Omenya Fredrick , Chernova Natasha A. , Zhou Hui , Siu Carrie , Whittingham M. Stanley 
Published: February 2020

LiCoO2 has conquered the cathode market for lithium ion batteries; recently the mixed transition metal oxide lithium nickel manganese cobalt dioxide have gained attention due to their superior electrochemical properties, better thermal stability, and lower cost. Nickel-rich compositions of lithium nickel manganese cobalt oxide (NMC) have been developed as promising high-energy, high-voltage and improved rate cathode materials capable of significantly increasing the energy density of lithium-ion batteries.
Here we report a systematic comparative study on rate capability, charge discharge behavior and nickel/lithium mixing of the nickel-rich layered oxides, NMC622, NMC811 and NCA. The results showed that both NMC622 and NMC811 have pure hexagonal layered phase with Ni/Li mixing below 4%. Both samples have similar specific capacity of about 220 mAh/g at current densities, C/10; however, NMC811 demonstrated superior electrochemical performance compared to NMC611 at higher rates. The 622 sample showed a strong dependence on the electrode loading, higher electrode loading above 15 mg/cm2 had poor performance compared to lower loading at the same current density in mA/cm2 while NMC811 sample does not show such loading dependence. This work was supported by the DOE-EERE-Battery500 consortium.
New Additives for Li Ion Batteries
Authors: Liao Chen , Shkrob Ilya A , Sahore Ritu , Tornheim Adam , Abraham Daniel P , Zhang Zhengcheng 
Published: February 2020

None of the battery chemistry would be possible without the component of electrolyte and additive, which is responsible for the formation of Solid Electrolyte Interface (SEI), the interface between the electrodes and the electrolyte. Studies have showed that EC would be reduced at ~ 0.7 V vs Li/Li+, and the reduction of EC forms SEI consisting of organic polymer, inorganic salts that serves as a filter for lithium ion conducting. The typical electrolyte consists of 1.0 to 1. 2 M of a lithium salt (such as LiPF6 or lithium bis(trifluoromethylsulfonyl)imide, LiTFSI) in mixed solvents of carbonates type. For example, the current prevalent electrolyte Gen 2 consists of 1.2 M LiPF6 in 30 wt % of ethylene carbonate (EC) and 70 wt % of ethyl methyl carbonate (EMC). Another vital role of the additive is to mitigate unavoidable electrolyte decomposition occurred both at anode and cathodes side during the charge/discharge process. Apparently, the quality of the SEI significantly affects the battery performance.
We are reporting a series of new additives for lithium ion batteries, and the ability of the additives to mitigate the presence of HF in the electrolyte was probed by solution-state nuclear magnetic resonance (NMR) spectroscopy. A galvanostatic charge/discharge protocol cycled between 3.0-4.4V at 30°C with periodic hybrid pulse power characterization (HPPC) tests gave electrochemical information from which capacity and impedance data were derived. Investigation of the harvested electrodes using X-ray photoelectron spectroscopy (XPS) after being cycled shed light on surface films formed and transition metal dissolution.
Oxidatively Stable Fluorinated Sulfones Electrolytes for High Voltage High Energy Li-Ion Batteries
Authors: Su Chi-Cheung , He Meinan , Tornheim Adam , Cao Jiyu , Redfern Paul , Curtiss Larry A , Shkrob Ilya A , Zhang Zhengcheng 
Published: February 2020

Developing a high-voltage enabling electrolyte is extremely critical for the success of the next generation high-energy density lithium-ion battery especially for electric vehicles. Material scientists have developed new cathode materials with improved specific capacity[1,2] and operating voltage (5 V vs. Li+/Li).[3,4] However, designed for a 4V-class lithium-ion chemistry, the conventional electrolyte suffers from oxidation instability on the charge cathode/electrolyte interface at high charging voltages which leads to severe transition metal (TM) dissolution and rapid capacity fading. The voltage instability of electrolyte becomes the bottleneck for the extensive application of the high voltage cathode materials. Thus, new electrolytes with elevated voltage stability has been widely explored.[5-8]
Here we report a new class of fluorinated electrolytes comprising novel fluorinated sulfones including ((trifluoromethyl)sulfonyl)ethane (FMES), 1-((trifluoromethyl)sulfonyl)propane (FMPS) and 2-((trifluoromethyl)sulfonyl)propane (FMIS).[9] These compounds have been synthesized via new synthetic routes and evaluated as electrolyte materials under high voltage operation. The results indicate that sulfones with an α-trifluoromethyl group possess enhanced oxidative potential and reduced viscosity as compared to their non-fluorinated counterparts. The α-fluorinated sulfones also show enhanced wetting ability with polyolefin separator. A facile synthesis method for a reported sulfone 1,1,1-trifluoro-3-(methylsulfonyl)propane (FPMS) was also developed. With the new reaction method, large quantity of material was obtained and comprehensive electrochemical properties of FPMS as high voltage electrolyte was evaluated. Unlike the α-fluorinated sulfones, the γ-fluorinated sulfones resemble the property of the non-fluorinated ones.

References:

[1] Nyten, A.; Abouimrance, A.; Armand, M.; Gustafsson, T.; Thomas, J. O. Electrochem. Commun., 2005, 7, 156-160.
[2] Ellis, B. L.; Makahnoul, R. M.; Makimura, Y.; Toghill, K.; Nazar, L. F., Nat. Mater., 2007, 6, 749-753.
[3] Hu, M.; Pang, X.; Zhou, Z. J., Power Sources, 2013, 237, 229-242.
[4] Santhanam, R.; Rambabu, B. J., Power Sources, 2010, 195, 5442-5451.
[5] He, M.; Su, C. C.; Feng, Z.; Zeng, L.; Wu, T.; Bedzyk, M. J.; Fenter, P.; Wang, Y.; Zhang, Z., Adv. Energy Mater.,
2017, 7, 1700109.
[6] He, M.; Su, C. C.; Peebles, C.; Feng, F.; Connell, J. G.; Liao, C.; Wang, Y.; Shkrob, I. A.; Zhang, Z., ACS Appl. Mater. Interface, 2016,
8(18), 11450-11458.
[7] Kunduraciz, M.; Amatucci, G.G., J. Electrochem. Soc.,
2006, 153, A1345-A1352.
[8] Wolfenstine, J.; Aleen, J., J. Power Sources, 2005, 142, 389-390.
[9] Su, C. C.; He, M.; Redfern, P. C.; Curtiss, L. A.; Shkrob, I. A.; Zhang, Z., Energy Environ. Sci.,
2017, 10, 900-904.

Figure 1
(Invited) High Voltage Aqueous Batteries
Authors: Xu Kang 
Published: February 2020

High voltage energy storage devices have always been supported by non-aqueous electrolytes, whose intrinsic wide stability window as well as the capability to form protective interphases at extreme potentials ensures the reversibility of electrochemical reactions, but whose high flammability, toxicity and sensitivity to ambient also bring compromises of safety, environment and rigid-format.
Replacing non-aqueous solvents with water could provide an ideal resolution of these issues on materials level, if the water molecules could be electrochemically stabilized at potentials where ordinary aqueous electrolytes decompose. This talk will summarize the efforts in this direction, and the various high voltage aqueous battery chemistries thus enabled.
Insights into the Kinetics of Redox Mediation for Li-O2 Batteries: A Dems and RRDE Study
Authors: Bawol Pawel P. , Thimm Jan H. , Baltruschat Helmut 
Published: February 2020

Due to its theoretical high specific energy Li-O2 systems have generated much interest within the electrochemical community [1]. Understanding the fundamentals of this system is import to improve it. Therefore, much effort has been put into characterizing the products and the mechanism of the underlying electrolyte systems and electrodes (also by ourselves [2-5]). Recently in the electrolyte, soluble redox mediators were proposed as additives to improve the sluggish kinetics of the oxygen reduction reaction (ORR) as well as the oxygen evolution reaction (OER)[6, 7]. Although the impact of this redox mediators is impressive, very little is known about the underlying mechanism.
Therefore, we focused in this study our research in the mechanism of redox mediation of the ORR. We applied rotating ring disc technique (RRDE) as well as the differential electrochemical mass spectrometry (DEMS) to get insights into the kinetics of the mediated ORR and into the amount of consumed electrons per oxygen. The DEMS experiments were performed in a thin layer geometry without convective transport within the cell. In addition, the DEMS setup is highly sensitive to the gases formed during ORR and OER. At higher electrode potentials, the amount of evolved CO2 is reduced by adding a redox mediator to the electrolyte. We also observed that the amount of consumed oxygen is increased compared to the supporting electrolyte without redox mediator. In order to investigate the impact of the cationic charge density on the mechanism of the mediated ORR we also performed measurements in K+-, Mg2+-, Ca2+- containing electrolytes solutions. In our analysis of the data, we could calculate the share of current going into the mediation of the ORR. This analysis showed that for the investigated cations the amount of consumed electrons per oxygen molecule is 2 e-/O2. We found out, that the reaction speed of ORR could be influenced by changing the cation of the supporting electrolyte. The RRDE study revealed the generation of Li2O2 within the electrolyte volume through an analysis of the rotational dependency within the experiments.
[1] K. M. Abraham and Z. Jiang, J. Electrochem. Soc., 143, 1 (1996).
[2] P. Reinsberg, A. Weiss, P. P. Bawol and H. Baltruschat, J. Phys. Chem. C, 121, 7677 (2017).
[3] C. J. Bondue, P. P. Bawol, A. A. Abd-El-Latif, P. Reinsberg and H. Baltruschat, J. Phys. Chem. C, 121, 8864 (2017).
[4] C. Bondue, P. Reinsberg, A. A. Abd-El-Latif and H. Baltruschat, Phys. Chem. Chem. Phys., 17, 25593 (2015).
[5] H. M. A. Amin, C. Molls, P. P. Bawol and H. Baltruschat, Electrochim. Acta (2017).
[6] B. D. McCloskey and D. Addison, ACS Catalysis (2017).
[7] X. Gao, Y. Chen, L. Johnson and P. G. Bruce, Nat. Mater., 15, 882 (2016).
Micro-Patterning Technology and Conformal Protective Coating for Lithium Metal Electrodes
Authors: Park Joonam , Jin Dahee , Byun Seoungwoo , Roh Youngjoon , Ryou Myung-Hyun , Lee Yong Min 
Published: February 2020

Li metal is still one of promising anode candidates for advanced lithium secondary batteries due to its lowest potential (-3.045V vs. SHE) and high specific capacity (3860 mAh g-1). However, dendrite formation during Li deposition process is known to be the main knotty problem to be solved. To overcome this challenging issue, a variety of previous approaches such as protection layer on Li metal, electrolyte additives, all-solid-state electrolytes, etc. have been attempted consistently (see Figure). However, their improvement levels are limited and insufficient to apply them to commercial-level secondary batteries.
To control lithium deposition/stripping location in the lithium metal, we have already proposed a micro-patterning technology with micro-needle and micro-stamp. [1-2] When micro patterns are formed on the lithium metal, the lithium deposition/stripping reaction is preferentially taken place within the patterns. With a simulation tool, Comsol Multiphysics ®, we can provide some discussion on which dimension will lead to better electrochemical performance. In addition, we will share state-of-the-art experimental results based on thin lithium metals and electrolyte additives, together.

References

1) M.-H. Ryou†, Y.M. Lee†, Y. Lee, M. Winter, and P. Bieker, Advanced Functional Materials 25(6) (2015) 834
2) J. Park†, J. Jeong†, Y. Lee†, M. Oh, M.-H. Ryou, and Y.M. Lee, Advanced Materials Interfaces 3 (2016) 1600140

Figure 1