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Calcium silicate composited nano-Si anode with low expansion and high performance for lithium-ion batteries
Energy Materials and Devices 2023, 1(2): 9370019
Published: 30 January 2024
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SiO is a promising anode material for next-generation lithium-ion batteries (LIBs) with high-energy density. However, the passivation of silicon oxide in SiO remains challenging to reduce its irreversible reactions and volume expansion during cycling. In this work, a scalable approach is proposed to synthesize calcium silicate/nanosilicon composites (pSi@CaO) by transforming the SiO2 in disproportionate SiO into calcium silicate at 1000 ℃. The bulk-distributed calcium silicate in pSi@CaO can effectively inhibit nanosilicon expansion and enhance ionic transfer. The optimized pSi@20%CaO anode demonstrates a low electrode expansion of 12.3% upon lithiation and 7.6% upon lithiation after 50 cycles. It also exhibits excellent electrochemical stability, delivering a specific capacity of 808 mAh g−1 at 50 mA g−1 with an initial Columbic efficiency of 72% and maintaining 82% capacity after 500 cycles at 1 A g−1. The feasible CaO passivation strategy proposed in this work is expected to promote practical applications of Si-based anodes in high-performance LIBs.

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Effect of LiOH on Tantalum Doped Li7La3Zr2O12 Garnet Solid Electrolyte
Journal of the Chinese Ceramic Society 2022, 50(3): 769-774
Published: 24 January 2022
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Tantalum (Ta) doped Li7La3Zr2O12 (Ta-LLZO) ceramics were prepared via conventional solid-state reaction. LiOH was used as a lithium source and a sintering additive for ceramics. The effect of LiOH on the microstructure and ionic conductivity of Ta-LLZO ceramics was investigated. The results show that LiOH as a lithium source can promote the formation of cubic Ta-LLZO,and LiOH as a sintering additive can effectively improve the densification of ceramics. The dense cubic garnet Ta-LLZO ceramics were obtained by sintering at 1200 ℃ for 5 h. When the amount of the sintering additive is 6% (in mass fraction), the ionic conductivity of ceramics reaches 6.23×10–4 S·cm–1. It is indicated that Li7La3Zr2O12 prepared via solid-state reaction has a great potential in the application of all-solid-state lithium ion batteries.

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