Inside or Outside: Origin of Lithium Dendrite Formation of All Solid-State Electrolytes
Inside or Outside: Origin of Lithium Dendrite Formation of All Solid-State Electrolytes
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内部或外部：所有固态电解质的锂枝晶形成的起源
DOI：
10.1002/aenm.201902123
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发表时间：
2019-09-03
影响因子：
27.8
通讯作者：
Sun, Dalin
中科院分区：
文献类型：
--
作者：
Mo, Fangjie;Ruan, Jiafeng;Sun, Dalin
全固态锂金属电池（asslmb）在下一代储能系统中脱颖而出。然而，锂枝晶在固态电解质中形成的机制仍然存在争议，这严重阻碍了锂枝晶的进一步实现。本文通过实验和理论方法，阐明了具有代表性的LiBH4 SSE中枝晶形成的起源，LiBH4 SSE与Li金属具有热力学稳定性，抑制了Li与SSE之间的副反应。结果表明，Li+在扩散过程中遇到电子，随后在SSE的晶界/孔内还原为Li-0，最终导致短路。因此，在SSE中引入具有间隙填充能力和低电子导电性的LiF是有效的对策，并且正如预期的那样，随着LiF的加入，临界电流密度（CCD）比纯LiBH4提高了235%。TiS2|LiBH4-LiF|Li asslmb在0.4℃下循环60次，具有137 mAh g（-1）的可逆容量。这些发现不仅揭示了SSE中Li枝晶形成的关键问题，而且提出了对策。
All-solid-state lithium metal batteries (ASSLMBs) stand out for the next generation of energy storage system. However, the further realization is severely hampered by the lithium dendrite formation in solid state electrolytes (SSEs), by mechanisms that remain controversial. Herein, with the aid of experimental and theoretical approaches, the origin of dendrite formation in representative LiBH4 SSE, which is thermodynamically stable with the Li metal, suppressing the side reaction between Li and SSE is elucidated. It is demonstrated that upon diffusion, Li+ encounters an electron, and is subsequently reduced to Li-0 within the grain boundary/pore of SSE, eventually leading to short circuit. Thus, introducing LiF with the ability of interstitial filling and low electronic conductivity into SSE is the effective countermeasure, and as expected, with the addition of LiF, the critical current density (CCD) increases by 235% compared to the value of pure LiBH4. The TiS2|LiBH4-LiF|Li ASSLMBs manifest a reversible capacity of 137 mAh g(-1) at 0.4 C upon 60 cycles. These findings not only unravel critical issues in Li dendrite formation in SSE, but also propose the countermeasure.