Ge2Sb2Se5 Glass as High-capacity Promising Lithium-ion Battery Anode

• DOI: 10.1016/j.nanoen.2019.104326
• Publication Date: 2019-11-27T16:33:22Z
• Authors: Jassiel R. Rodriguez; Zhimin Qi; Haiyan Wang; Mikhail Y. Shalag...; Claudia Goncalves; Myungkoo Kang; Kathleen A. Richa...; J. Guerrero-Sanchez; Ma Guadalupe More...; Vilas G. Pol
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract Conventional alloying and conversion Li-host anode materials have been extensively studied as high capacity lithium ion battery anodes. However, they suffer continuous volume change during each charge-discharge process, triggering the electrode pulverization and loss of their capacity upon cycling. Interestingly, investigations on glass materials as Li-host anodes are less prevalent, although their disorder structure can help to accommodate their volumetric expansion and maintain the anisotropic particle arrangement with a better distribution during Li-ion insertion and extraction. Here, we report attributes of a promising candidate chalcogenide glass material, Ge2Sb2Se5, which exhibits a reversible high capacity of 626 mAh g−1 at a 0.5 C-rate, displays a capacity retention of 80% with a coulombic efficiency of >99% after 100 cycles. The resulting material performance is explained by a proposed lithiation mechanism in which lithium ions are alloyed with Se atoms at high potential, followed by the lithiation of Sb and Ge as the potential decreases during the discharge process. DFT calculation suggests an optimized glassy cell unit of Ge2Sb2Se5 with an energy gap of 0.14 eV, proposing a possible arrangement of atoms with short range order, in which the large variation of the nearest neighbor distances in Ge2Sb2Se5 can promote its stable anodic performance.