In-situ constructed a cross-linking Li3N-LiF network inducing stable cathode/electrolyte interphase for hybrid solid-state lithium batteries

The hybrid solid -state lithium batteries (SSLBs) concept is one of the promising approaches for promoting interfacial contact of solid -state electrolyte (SSE)/cathode, whereas the Li -ion transport is slackened by the poor cathode/electrolyte interphase (CEI) film. Herein, we in-situ construct a cross-linking Li3N-LiF network for fabricating a thin and uniform CEI film to improve cycling stability and maintain electrochemical reversibility. The Li3N is generated from the in-situ formed LiNO3 sustained-release layer on the garnet SSE Li6.5La3Zr1.5- Ta0.5O12 (N-LLZTO) surface, while the LiF is produced by the decomposition of LiPF6 salt dissolved in the carbonate-based electrolyte. The abundant inorganic LiF alleviates strain/stress induced by the volume change of the cathode. The Li3N with high ionic conductivity compensates for the low kinetics of the CEI film composed of sole LiF. The hybrid Li/N-LLZTO/LiFePO4 SSLBs exhibit a remarkable lifespan of 400 cycles with a 95.06 % capacity retention at 0.5 C.