bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparision and Characterization of Carbon-Coated LiMnxFe1-XPO4 (x= 0.4) Between Different Synthesis Routes
Authors: Penumaka Rani v , Lastres Miguel P , Bhattacharya Indranil 
Published: February 2020

LiMnxFe1-xPO4 (x=0.4) (LMFP) solid solution system of olivine transition metal phosphates are considered to be very attractive cathode materials owing to their high redox couple and high theoretical capacity of 170mAh/g .With inherent low cost, stability at high temperatures, high energy density and non-toxic nature these materials are highly suitable for plug-in hybrid vehicles. Nevertheless, due to the low electrical conductivity and low Li ion diffusion kinetics makes these materials unsuitable for practical applications. In this research, carbon coated LMFP was synthesized by a modified solid state and a surfactant based sol-gel technique. The cathode materials obtained were characterized and performance was compared and evaluated. The materials obtained by both the processes showed similar morphologies and excellent cycle stability. The cathode materials prepared by sol-gel process delivered the best electrochemical performance when compared to solid state process.
Low Temperature Synthesis and Characterization of Carbon-Coated LiMnPO4 for Lithium-Ion Batteries
Authors: Penumaka Rani v , Lastres Miguel P , Bhattacharya Indranil 
Published: February 2020

LiMnPO4 based phospho olivines are considered to be environmentally friendly, and low cost potential cathode material for the next generation of Li-ion secondary batteries to meet the huge market of electric and hybrid vehicles [1, 2]. The relatively higher operation voltage at around 4 V makes the theoretical specific energy of LiMnPO4 (684 Wh/kg) 20% greater than that of LiFePO4 (578 Wh/kg) while still compatible with most conventional electrolytes [3]. However, due to the low electrical conductivity and poor Li ion diffusion kinetics these materials are unsuitable for practical applications [4]. In here, carbon coated LiMnPO4 was synthesized by both solid state and modified sol-gel technique using a low temperature synthesis techniques. The cathode materials obtained were characterized and performance was compared and evaluated. Results of the electrochemical tests show that the prepared LiMnPO4/C (around 10 wt. % carbon) composites by both the routes exhibits not only a high initial discharge capacity but also good cycling stability. Although highly crystalline phase pure cathode materials could be obtained by both the processes, the materials prepared by sol-gel process delivered slightly better electrochemical performance when compared to solid state process.
References:
[1] C. Delacourt, P. Poizot, M. Morcrette, J. M. Tarascon and
C. Masquelier, Chem. Mater., 2004, 16, 93.
[2] J. Xiao, W. Xu, D. Choi and J.-G. Zhang, J. Electrochem. Soc.,
2010, 157, A142.
[3] Xiao, Jie, et al. Physical Chemistry Chemical Physics 13.40 (2011): 18099-18106.
[4] J. Yang, J.J, Journal of The Electrochemical Society 153 (4) (2006) A716–A723
A Novel Li-Metal Alloy Battery with Ultra-Long Cycles at High Rates
Authors: Niu Junjie 
Published: February 2020

Carbon emission from non-renewable energy sources such as gasoline due to the drastically increasing energy demand becomes a critical issue in the world. This necessitates researchers to develop an environmental friendly energy storage that can meet the requirement for large devices particularly EVs. However, the current LIBs can’t provide sufficient energy density due to a limiting capacity of 372 mAh/g from graphite anode. Therefore, searching novel electrode materials for large energy storage that can deliver much higher capacity becomes very urgent. Sn has a 3 times greater capacity of ~1000 mAh/g that poses one of primary candidates for the next-generation LIBs. Sony released the first commercial amorphous Sn based battery called Nexelion that shows a 30% improved capacity than conventional graphite based battery in 2005. Scientists have made numerous attempts to stabilize the Sn alloy geometry by constructing nano-structures with carbon nanotubes, graphene, nanorods, nanocores, metal forms and metal alloy scaffold.
Here we present a novel Sn cage (Sn-NC) configuration comprising an industrially available, pure metal Sn and an oxide surface (not SnOx). Through the in-situ TEM study on 3D Sn matrix, we found a well-designed space can accommodate the morphology change during the charging/discharging process (Liu, Nano Lett 2016). The protection of the rigid oxide surface and the adjustable interspace can prevent the pulverization and oxidation of the metal while supplying a fast Li+/e- pathway. The coin/punch cells using Sn-NCs as anode provide a high capacity up to >600 mAh/g after ultra-long 5000 cycles at a high charge/discharge rate. The mass production of this anode material opens an avenue for industrial applications.
Mechanistic Insights into Oxygen Reduction and Evolution Reactions in Non-Aqueous Metal-Air Batteries
Authors: Zhang Yelong , Zhang Xinmin , Wang Jiawei , Ma Shunchao , Guo Limin , Rawal Saurin , McKee William C. , Xu Ye , Peng Zhangquan 
Published: February 2020

Non-aqueous metal-air batteries have generated strong research interest because they possess much greater theoretical gravimetric energy storage density than today’s rechargeable battery technologies.1-4 This has re-kindled research into the fundamentals of oxygen reduction and evolution reactions (ORR and OER) in non-aqueous electrolytes because they are the central electrochemical processes at metal-air cathodes. Understanding the reaction mechanisms is critical to improving cycling efficiency and making rechargeable metal-air batteries a reality.
We will present the results of a series of electrochemical studies of the ORR/OER on a gold electrode in strictly dry, non-aqueous dimethyl sulfoxide (DMSO) electrolytes containing different cations, including H+, Li+, and Na+,5,6 using in situ spectroelectrochemistry and first-principles calculations and theoretical modeling. Significantly the ORRs share a common characteristic, namely the superoxide anion (O2
-), the one-electron reduction product of O2, is the first O2 reduction product to form. It has several important consequences: O2
- thus controls the onset potential of the ORR, and its solubility in the electrolyte makes solution-phase reactions involving O2
- an integral part of the electrode processes at low overpotentials, including the formation of superoxides and peroxides (via disproportionation of the superoxides) away from the cathode. On the other hand, there is a clear contrast between Li+ and Na+: Whereas the main reduction product is Li2O2 for Li+, which requires a high overpotential to be oxidized, the reduction product for Na+ is predominantly NaO2, whose high solubility in DMSO alleviates solid buildup on the electrode and also facilitates the oxidation of NaO2. Consequently the Na+ O2 cathode is much more reversible than its Li+ counterpart. The energetic factors controlling the formation of O2
-, solution vs. surface reaction pathways, and the lack of Na2O2 formation will be discussed. Overall, our studies reveal that the ORR/OER mechanisms depend intimately on the cation, potential, and electrolyte, and contribute new mechanistic understanding to the eventual realization of reversible metal-air battery technologies.
1. P.G. Bruce, S.A. Freunberger, L.J. Hardwick, J.-M. Tarascon, Nat. Mater. 2012, 11, 19.
2. J. Lu, L. Li, J.-B. Park, Y.-K. Sun, F. Wu, K. Amine, Chem. Rev.
2014, 114, 5611.
3. A.C. Luntz, B.D. McCloskey, Chem. Rev.
2014
, 114, 11721.
4. R. Black, B. Adams, L.F. Nazar, Adv. Energy Mater.
2012, 2, 801
5. Z. Peng, Y. Chen, P.G. Bruce, Y. Xu, Angew. Chem. Int. Ed.
2015, 54, 8165.
6. Y. Zhang, X. Zhang, J. Wang, W.C. McKee, Y. Xu, Z. Peng, J. Phys. Chem. C
2016, 120, 3690.
Three-Dimensional Lithium-Iodine Microbatteries for Implantable Devices
Authors: Citrin Michael A , Greer Julia R 
Published: February 2020

Conventional batteries use thick electrodes that provide high energy density, but have large ion transport lengths that limit their current densities. Thin film batteries utilize thin layers of material and small transport lengths for higher power, but are limited in their total energy due to low mass loading. Three-dimensional batteries combine both high mass loading and small ion transport lengths due to their architected design, allowing for both high energy and power densities over a small footprint area. Accessing height in battery design permits much more active material than a planar thin film battery. Modern nanofabrication techniques, such as two-photon lithography, can fabricate 3D structures at the micro and nano scale that can be incorporated into a small-scale architected 3D cell. This type of battery could power the next generation of bio-implantable devices and miniaturized wearable sensors.
We demonstrate the fabrication of architected anodes using two-photon lithography to form a polymer scaffold. A gold layer on the nickel current collector alloys with lithium, creating an adhesion layer that assists lithium electrodeposition. The cathode used is iodine mixed with poly(2-vinylpyridine) (P2VP), which forms a lithium iodide solid electrolyte in situ when the anode and cathode come in contact and can be poured into the structure in its molten state. The geometry of the anode is determined by surface area and the pore size is determined to accommodate the thickness of the lithium iodide layer and infiltration of cathode. The increase in surface area and decrease in ion transport lengths from the 3D architecture provide improved performance of the primary battery over planar cells with the same footprint area. Other battery chemistries could be investigated with such a battery design to enhance performance.
Investigation of Oxidizing Graphene Halides for Li/S Batteries
Authors: Pardo Eduardo , Thai Edward , Dunham Nathanael , Alonso Josue , Garcia Jonathan , Dinh Andrew , Yu Ted H. 
Published: February 2020

Lithium-sulfur batteries1 are a potential game-changer in rechargeable lithium battery technology. In addition to being very low cost due to the abundance of sulfur, it also has a higher theoretical specific capacity (1674 mAh/g-sulfur) than traditional lithium-ion batteries. In the last five years, incorporating graphene oxide2
,
3 (GO) has been an effective strategy to prolong the life of lithium-sulfur batteries, which improves overall performance and battery stability. However, current methods of GO synthesis, such as the Hummers method2, are not cost-effective. New research explores the use of graphene halides4to replace GO. The graphene halides used in this study can be produced through a simple ball-mill process which is easily scalable. Our studies show that out of the halides, graphene-iodide (GI) has performed remarkably well in cycle performance with its ability to retain capacity after subsequent charge/discharge cycles when compared to graphene bromide and graphene chloride.
We attempted to increase the cycle life and performance of our cathodes by using a technique to reintroduce oxygen functional groups on the GI basal planes. Through NO2 adsorption followed by UV treatment, we have been able to create carbon-oxygen functional groups to synthesize epoxidic, hydroxyl, and carbonyl carbon-oxygen bonds on graphene halides. This alternative method to oxidation uses fewer resources than the traditional Hummers method, which will reduce cost and environmental impact. The oxidized GI outperformed the non-oxidized GI based cathodes in its ability to maintain discharge capacity over time as seen in Figure 1.

Figure 1
Novel Lithium Manganese Silicate with Stable Structure upon Cycling As Positive Electrode for Lithium-Ion Batteries
Authors: Lefèvre Guillaume , Ducros Jean-Baptiste , Boulineau Adrien , Benayad Anass , Martinet Sebastien 
Published: February 2020

Lithium manganese silicate Li2MnSiO4 is theoretically one of the most interesting polyanionic material for lithium-ion batteries positive electrode. Its theoretical capacity reaches 333mAh/g thanks to the possible exchange of two lithium ions per formula unit which happens below the organic electrolyte degradation voltage. Indeed, the first lithium ion is calculated to be exchanged at 4.1V vs Li+/Li and the second one at 4.4V [1]. The high energy density combined with the thermal stability of the Si-O bond make Li2MnSiO4 in theory one of the best choice to equip the next generation of electrified transportation [2].
1st studied in 2006 by Dominko et al. [3], lithium manganese silicate still shows severe limitations. Both its ionic and electronic conductivities are low [4] and Li2MnSiO4 structure cannot accommodate large Li+ extraction without amorphization. Thus, it leads to high polarization and capacity fading during cycling, impeding its practical interest. Despite this trend, manganese-based silicate polyanions are essentially interesting because of their high abundance, low cost and environmental friendliness.
Here we propose an unreported manganese silicate material that we recently patented. This new material, usable as a positive electrode for lithium ion batteries, showed remarkable cycling stability. 100 mAh/g were obtained in half-cells versus lithium metal counter-electrode (Figure 1). Ex-situ X-Ray Diffraction showed that the structure was maintained during cycling, demonstrating that the material can accommodate reversible extraction of Li+ ions. To limit particle growth careful attention was paid on the synthesis route. Primary particles of 50 nanometers were obtained by a sol-gel process (Figure 2). Rate capabilities of the material, studied by galvanostatic cycling, will also be presented. Deeper characterization by X-Ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy-Selected Area Electron Diffraction (TEM-SAED) and Differential Scanning Calorimetry (DSC) will be shown to assess the redox process, structure and thermal stability of this material.
[1] Arroyo-de Dompablo et al., Electrochem. Commun., 2006, 8, 1292–1298
[2] Andre et al., J. Mater. Chem. A, 2015, 3, 6709–6732
[3] Dominko et al., Electrochem. Commun., 2006, 8, 217–222
[4] Dominko et al., J. Power Sources, 2008, 184, 462–468

Figure 1
Optimizing the Electrolyte for Glucose-Derived Carbon Based Na-Ion Battery
Authors: Väli Ronald , Thomberg Thomas , Jänes Alar , Lust Enn 
Published: February 2020

Sodium-ion batteries have attracted great deal of attention due to sodium’s abundance and lower price compared to lithium and cobalt. A major obstacle that prevents sodium-ion batteries going to a mass-scale is the negative electrode (anode during discharge). Graphite is currently the safest negative electrode material for lithium-ion batteries, but does not intercalate sodium reversibly, because sodium ions prefer prismatic or octahedral coordination sites [1].
Our previous work [2] focused on the synthesis and electrochemical characterization of glucose-derived hard carbon negative electrodes for sodium-ion batteries. Unfortunately, the tested electrochemical half-cell showed high capacity fade during cycling. At the time, we thought it was due to material’s spherical morphology (Fig. 1a). But when we substituted the previously used electrolyte (1M NaClO4 in PC) with 1M NaPF6 in PC:EC (9:1) capacity fade was significantly reduced. The discharge capacity for the 100th discharge cycle was only 177 mAh g-1 when using NaClO4 in PC, but remained at 267 mAh g-1 when using NaPF6 in PC:EC (9:1) (Fig. 1d - e).
The results of full cell testing with NVP-type cathode [3] will also be discussed.

Acknowledgements

This research was supported by the EU through the European Regional Development Fund TK141 “Advanced materials and high-technology devices for energy recuperation systems”, Estonian target research project IUT20–13 and personal research grant PUT55. Mr. Väli thanks Estonian Students Fund in USA and University of Tartu Foundation for financial support.

References

1. J. Qian, X. Wu, Y. Cao, X. Ai, and H. Yang, Angew. Chem. Int. Ed., 52, 4633 (2013).
2. R. Väli, A. Jänes, T. Thomberg, and E. Lust, J. Electrochem. Soc., 163, A1619 (2016).
3. R. Väli, P. Möller, and A. Jänes, ECS Trans., 69, 27 (2015).

Figure 1
Application of Ordered Intermetallic Nanoparticles to Polymer Electrolyte Fuel Cells
Authors: Liu Yubin , Gunji Takao , Tsuda Takashi , Tanabe Toyokazu , Kaneko Shingo , Ohsaka Takeo , Matsumoto Futoshi 
Published: February 2020

Our recent investigations of electrocatalysts for low temperature fuel cells have shown that ordered intermetallic compounds such as PtBi and PtPb have lower oxidation onset potentials and higher current densities for formic acid oxidation than pure Pt and Pd electrodes1
,2). In this presentation, carbon black (CB)-supported Pt3Pb NPs was synthesized as catalysts for the formic acid oxidation and oxygen-reduction reaction. Atomically disordered and ordered intermetallic Pt3Pb NPs were prepared at room temperature using the polyol method. The Pt/carbon black (CB) and Pb(CH3COO)2•3H2O were dissolved in ethylene glycol. The mixture was sonicated and then treated in the flask under reflux for 1 min with 300-W microwave radiation. The mixture in the flask was cooled to room temperature with water. The mixture was again treated with microwave radiation (focused microwave instrument, CEM) at 300 W for 9 min. After the mixture cooled, Pt3Pb NPs/CB was collected by centrifugation, washed sequentially with methanol and dried under vacuum. The formation of ordered intermetallic Pt3Pb after annealing was confirmed by X-ray photoemission spectroscopy, powder X-ray diffraction, and a scanning transmission electron microscope with an electron-probe microanalyser (STEM). The surface structure of atomically disordered and ordered intermetallic Pt3Pb NPs was analyzed with high-resolution STEM. The relationship between the electrocatalytic activity and the surface structure was examined.
(1) Fuma Ando, Takao Gunji, Hikaru Fujima, Tsuyoshi Takeda, Toyokazu Tanabe, Shingo Kaneko, Futoshi Matsumoto, Preparation of PtPb/TiO2/Cup-Stacked Carbon Nanotube Composite for Enhancement of Electrocatalytic Reaction of Oxygen Reduction Reaction, Chem Lett., 44(12), 1741-1743(2015).
(2) Takao Gunji, Toyokazu Tanabe, Arockiam John Jeevagan, Sho Usui, Takashi Tsuda, Shingo Kaneko, Govindachetty Saravanan, Hideki Abe, Futoshi Matsumoto, Facile Route for the Preparation of Ordered Intermetallic Pt3Pb-PtPb Core-Shell Nanoparticles and Its Enhanced Activity for Alkaline Methanol and Ethanol Oxidation, J. Power Sources, 273, 990-998(2014).
(Invited) Polymer Wrapped Carbon Nanotubes As Highly Effective Hole Transporting Layers for New Perovskite and Quantum Dot Photovoltaic Devices
Authors: Nicholas Robin J , Habisreutinger Severin N , Noel Nakita K , Snaith Henry J , Watt Andrew , Tazawa Yujiro , Zhang Nanlin 
Published: February 2020

Our recent work (1) has shown that polymer wrapped carbon nanotubes can be used to transform the properties of the hole transporting layer in a number of different perovskite based solar cell configurations. This presentation will report on two examples where the CNT hole transporter produces enhanced device performance, firstly for tin oxide/perovskite alloy/CNT devices and secondly in PbS colloidal quantum dots (CQD) where improved charge extraction by the CNT is particularly important.
Halide perovskite solar cells remain to generate a lot of interest and enthusiasm among researchers, largely due to the prospect of readily transitioning from a purely lab based technology to real-world scales. This expectation is largely based on the rapid increase in efficiency over the past few years to values above 22%. An essential component of this device architecture are the two charge selective contacts. The n-type contact in the majority of all devices is TiO2, either as a thin compact layer, or a mesostructured configuration, but recently, SnO2 has moved into the spotlight as n-type contact with recent studies reporting excellent steady-state performances.
The p-type contact on the other side of the absorber has been investigated even more intensively. The best-performing devices still use the “original” hole-transport material, spiro-OMeTAD, which provided the crucial breakthrough for the perovskite solar cell in 2012, but which suffers from the fact that it is not sufficiently conductive for efficient charge-transport, and requires extrinsic doping, typically with Li-TFSI, which has been shown to detrimentally impact the device stability. This presentation will demonstrate that for FA0.83MA0.117Pb(I0.87Br0.17)3 based solar cells we can achieve steady-state efficiencies of up to 18.8%, by using polymer-wrapped single-walled carbon nanotubes (SWNTs) as an inert conductive element in undoped spiro-OMeTAD, exceeding the performance of their fully doped counterparts.
In a completely different example we can use the same polymer wrapped SWNTs as a hole collection electrode for PbS based CQD photodetectors which are capable of operating over a spectral range extending beyond one micron. We find that the use of a polymer wrapped CQD combined with PMMA filler more than doubles the current collection in such devices and enables efficiencies of over 7%. In addition the SWNT layer produces a substantial improvement in long term device stability in normal ambient conditions.
(1) Habisreutinger, S. N.; Leijtens, T.; Eperon, G. E.; Stranks, S. D.; Nicholas, R. J.; Snaith, H. J. Nano Lett.
2014, 14, 5561–5568.
(Invited) Less Is More: Thermoelectric Performance Enhancements in Polymer-Free Semiconducting Single-Walled Carbon Nanotube Networks
Authors: Ferguson Andrew John , Norton-Baker Brenna , Ihly Rachelle , Gould Isaac E. , Stanton Noah J. , MacLeod Bradley A. , Avery Azure D. , Owczarczyk Zbyslaw R. , Blackburn Jeffrey L. 
Published: February 2020

There is a growing interest in the use of carbon nanostructures for a variety of electronic and optoelectronic technologies, including energy harvesting applications such as photovoltaics (PV) and thermoelectrics (TE). We will present a series of studies aimed at improving the TE performance of semiconducting single-walled carbon nanotube (s-SWCNT) thin film networks.
The optical and electrical performance of SWCNT ensembles is often limited by the presence of metallic single-walled carbon nanotube (m-SWCNT). We will demonstrate a polymer-based purification strategy that effectively eliminates these, and other impurities, from the raw material, leaving s-SWCNTs in extremely high purity. Modification of this extraction process produces s-SWCNT thin film networks where the polymer can be completely removed, resulting in close tube-tube contacts in a dense s-SWCNT network. Removal of the polymer in the solid state, rather than in solution, also minimizes nanotube bundling during network formation. By controlling the bundle size and extent of polymer remaining in the s-SWCNT network we demonstrate TE power factors that almost double the performance of s-SWCNT networks previously demonstrated. We trace the improved performance to an enhanced electrical conductivity, resulting from improved doping and strongly enhanced charge carrier mobility, and analyze our data within the framework of a recently developed thermoelectric transport model. Finally, we demonstrate that the removal of the polymer from the s-SWCNT network has negligible impact on the thermal conductivity, which appears to be limited by dopant-induced phonon scattering processes.
These observations demonstrate the ability to exert exquisite control of the thermoelectric performance by controlling the composition of the s-SWCNT network and tuning the carrier density (i.e., Fermi energy), and touts SWCNTs as an avenue for realizing thermally stable room temperature thermoelectric devices fashioned from inexpensive and abundant organic constituents.