The shield-like nano-sized Si₃N₄ derivatives to defend against the attack of lithium dendrites

The unrestrained Li dendrite growth impedes the performance of Li metal batteries (LMBs) and brings safety concerns. To mitigate the unfavorable effect of Li dendrites, in this work, a shield-like artificial interlayer composed of Si₃N₄ is employed to achieve the desirable electrochemical performance of LMBs. The Si₃N₄-based interlayer can in-situ electrochemically react with Li to generate inorganic Li₃N and Li_xSi alloys: the former with high ionic conductivity can effectively enhance the Li⁺ transference, while the latter with reversibility for Li⁺ insertion/deinsertion can act as Li⁺ reservoir to modulate Li⁺ platting/stripping. Thus, the Si₃N₄-derived compound shield effectively defends against the attack of Li dendrites and suppresses their growth, with which the Li||Li cells can cycle at 1 mA cm^-2 (1 mAh cm^-2) up to 500 h and the LiFePO₄ (LFP) ||Li batteries can operate 400 cycles at 1C with 91.5 % capacity retention.