Constructing Superionic Heterointerface via Multiphase Engineering to Achieve Stable Oxyhalide-Based All-Solid-State...

Amorphous oxyhalides attract great interest as solid-state electrolytes (SSEs) in all-solid-state batteries (ASSBs) because of their oxidative stability, low cost, and mechanical deformability. But the limited room-temperature ionic conductivity and the parasitic reactions on cathode/halide interfaces impede their practical applications. Herein, we adopt a facile multiphase regulation strategy by incorporating ZrB₂ and ZrN into an amorphous 1.3Li₂O-ZrCl₄ (LZCO) matrix to simultaneously enhance Li⁺ transport and interfacial stability. ZrB₂ and ZrN regulate the bridging-oxygen/non-bridging-oxygen ratio to promote amorphization and create superionic heterointerfaces, which enables a more continuous Li⁺ conduction network while preserving overall electronic insulation. The multiphase architecture mitigates the interfacial side reactions, improves the interface compatibility due to the formation of B-O and N-O bonds, and homogenizes electron transport pathways in the composite cathode. As a result, 1.3Li₂O-0.8ZrCl₄-0.1ZrB₂-0.1ZrN (LZCOBN_0.1) shows a high room-temperature ionic conductivity of 2.41 mS cm^-1, compared with 1.3 mS cm^-1 for pristine LZCO. ASSBs employing LZCOBN_0.1 and LiNi_0.90Co_0.05Mn_0.05O₂ deliver a high initial capacity of 210 mAh g^-1 at 0.1 C and retain 82.7% capacity after 2000 cycles at 3 C, demonstrating ultrahigh cycling stability. This work highlights the potential of phase engineering regulation in developing high-performance amorphous oxyhalide-based ASSBs.