ORALS

SESSION: BatteryMonAM-R9	5th Intl. Symp. on Sustainable Secondary Battery Manufacturing and Recycling
Mon Nov, 5 2018 / Room: Asian (60/3rd)
Session Chairs: Vasant Kumar; Miles Freeman; Session Monitor: TBA

11:45: [BatteryMonAM02] Keynote
Preparation of High-Performance Cathode and Anode Materials for Sodium-Ion Batteries and Investigating the Reaction Mechanism
Ghulam Ali¹ ; Ji Young Kim¹ ; Hee-dae Lim¹ ; Kyung Yoon Chung¹ ; ¹Korea Institute of Science and Technology (KIST), Seoul, South Korea;
Paper Id: 389 [Abstract]

The demand for energy storage systems (ESS) has increased tremendously in the last decade due to their use in a variety of applications ranging from mid- to large-scale. The most important factors in the development of ESS include high-performance and cost-effective systems. At present, lithium-ion batteries (LIBs) are being used as storage devices but their application is limited to small- to medium-scale. The main reasons to not use LIBs at large-scale are high production cost and limited lithium resources. While searching for alternatives, sodium-ion batteries (SIBs) have emerged as a potential candidate for the use of ESS, which is considered cost-effective and also share similar electrochemical principle to LIBs. However, high-performance cathode and anode materials are urgently required for the commercialization of SIBs.
In the search of high-performance electrode materials, we have prepared several cathode and anode materials for SIBs. I will briefly discuss the preparation and electrochemical properties of the high-performance cathode materials, which include FeF₃.0.5H₂O and olivine-type NaFePO₄, and also discuss the investigated reaction mechanism. The nanocomposite of FeF₃.0.5H₂O and reduced graphene oxide has shown high sodium storage performance where it delivers a capacity of 266 mAh g^-1 while NaFePO₄ has shown excellent cyclability with a capacity retention of 94% after 100 cycles. Further, alloying-based SnF₂ anode material was prepared and the electrochemical properties, as well as reaction mechanism, were systematically investigated. The nanocomposite of SnF₂ and acetylene black has shown promising electrochemical performance where it delivers a high capacity of 563 mAh g^-1. In-situ XRD and synchrotron-based X-ray absorption spectroscopy (XAS) were used to investigate the reaction mechanism of the above-mentioned materials. The details of the investigated reaction mechanism will be discussed in my presentation.

References:
[1] Ali, G., S. H. Oh, S. Y. Kim, J. Y. Kim, B. W. Cho and K. Y. Chung, Journal of Materials Chemistry A 3(19): 10258-10266 (2015)\n[2] Ali, G., J. H. Lee, D. Susanto, S. W. Choi, B. W. Cho, K. W. Nam and K. Y. Chung, ACS Applied Materials & Interfaces 8(24): 15422-15429 (2016).\n[3] Ali, G., J. H. Lee, S. H. Oh, H. G. Jung and K. Y. Chung, Nano Energy 42: 106-114 (2017).

SESSION: BatteryMonPM1-R9	5th Intl. Symp. on Sustainable Secondary Battery Manufacturing and Recycling
Mon Nov, 5 2018 / Room: Asian (60/3rd)
Session Chairs: Claudio Capiglia; Jim Zheng; Session Monitor: TBA

14:25: [BatteryMonPM106]
Solution-based Synthesis of Li₃PS₄ Solid Electrolytes
Hee-dae Lim¹ ; Xing Xing² ; Ping Liu² ; ¹Korea Institute of Science and Technology (KIST), Seoul, South Korea; ²University of California, San Diego (UCSD), San Diego, United States;
Paper Id: 384 [Abstract]

Sulfide-based solid electrolytes have attracted much attention due to their high conductivities, which are far beyond those of oxide-based solid electrolytes. [1,2] However, They (Li₂S-P₂S₅ system, i.e., LPS) have been normally synthesized by solid state synthesis such as mechanical ball milling. These methods require rigorous control of reaction environment as well as high temperature heat treatment and repeated pelletizing steps. In contrast, solution-based synthesis methods can induce chemical reaction among precursor particles (Li₂S and P₂S₅) at low temperatures resulting in the formation of conductive phases of Li₃PS₄ and Li₃P₇S₁₁ with only moderate thermal treatment.[3,4] The method deserves great attention since it simplifies synthesis process, yields products of great purity, and may facilitate the fabrication of composite electrodes with improved interfaces. <br />In this work, we have developed an efficient method to form a thin solid electrolyte layer directly on Li metal using the liquid coating techniques. The formation of LPS (Li₂S-P₂S₅) based electrolyte is achieved by rational design of the solvent and the Li, P, and S precursor ratios. The solution electrolyte can be directly coated and formed on Li metal through the in-situ formation of the solid electrolyte layer, which does not require the complex synthesis process and high temperature sintering step. Layers of thickness of < 50 um can be fabricated and electrochemical cycling of lithium is achieved. This liquid-phase coating is a simple and straightforward technique for making a thin solid electrolyte and can be applicable to anode surface with complex contours. The new liquid coating technique holds the promise to overcome the limitations of current state solid electrolytes.

References:
[1] Kamaya, N. et al. A lithium superionic conductor. Nature Mater. 10, 682-686 (2011).\n[2] Yamane, H. et al. Crystal structure of a superionic conductor, Li7P3S11. Solid State Ion. 178, 1163-1167 (2007).\n[3] Ito, S. et al. A synthesis of crystalline Li7P3S11 solid electrolyte from 1,2-dimethoxyethane solvent. J. Power Sources 271, 342-345 (2014).\n[4] Liu, Z. et al. Anomalous High Ionic Conductivity of Nanoporous Li3PS4. J. Am. Chem. Soc. 135, 975-978 (2013).