In the pursuit of high-performance solid-state batteries (SSBs), which can have excellent safety and energy density, it is critical to understand the cyclability of emerging classes of solid-state electrolytes (SSEs). Lithium thioborates (LBS) are an understudied class of materials with promising applications in SSBs with lithium metal anodes. We investigate the electrochemistry, structure, and cyclability of the LBS SSE with stoichiometric Li₁₀B₁₀S₂₀ with lithium iodide (LiI) as an additive. LBS-LiI exhibits an outstanding ionic conductivity of 1.0 mS cm^–1 due to increased LBS crystallinity and favorable modification of the LBS grain boundaries with LiI. LiI improves the cycling stability against lithium metal anodes, limits dendrite growth with a high critical current density of 2.0 mA cm^–2, and cycles well in cells with LiNi_0.6Mn_0.2Co_0.2O₂ (NMC) 622 cathodes and indium anodes. Our work highlights LiI as a grain boundary modification in LBS solid electrolytes and demonstrates the promising cyclability of LBS-LiI in SSBs.

中文翻译：

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一种新型高离子电导率锂金属电池硫硼酸锂-碘化锂固态电解质

为了追求具有出色安全性和能量密度的高性能固态电池（SSB），了解新兴固态电解质（SSE）类别的可循环性至关重要。硫代硼酸锂 (LBS) 是一类尚未得到充分研究的材料，在具有锂金属阳极的 SSB 中具有广阔的应用前景。我们研究了以化学计量的 Li ₁₀ B ₁₀ S ₂₀和碘化锂 (LiI) 作为添加剂的LBS SSE 的电化学、结构和循环性能。由于 LBS 结晶度增加以及 LiI 对 LBS 晶界的有利修饰， LBS-LiI 表现出 1.0 mS cm ^–1的出色离子电导率。 LiI 可提高锂金属阳极的循环稳定性，以 2.0 mA cm ^{–2的高临界电流密度限制枝晶生长，并且在采用 LiNi} _0.6 Mn _0.2 Co _0.2 O ₂ (NMC) 622 阴极和铟阳极的电池中循环良好。我们的工作强调了 LiI 作为 LBS 固体电解质中的晶界修饰，并展示了 LBS-LiI 在 SSB 中的良好循环性能。