Dual Optimization of Electrolyte and Interface in Na‐ β ″‐Al 2 O 3 via Ga 3+ Doping for Advanced Solid‐State Sodium Batteries

作者：Shangqing Qu, Tianhao Niu, Xianji Qiao, Yanran Shen, Guohong Cai, Guohong Cai, Xiaoge Wang, Yonggang Wang, Zhipeng Zhou, Shipeng Zhang, Zeyue Zhang, Guobao Li, Guanqun Cai, Guanqun Cai, Junliang Sun · 发表于：Advanced Materials · 年份：2025 · DOI：10.1002/adma.202503562 · 被引用次数：7 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Inorganic Chemistry and Materials

Abstract Na‐ β ″‐Al 2 O 3 is a highly promising solid‐state electrolyte (SSE) for solid‐state sodium batteries (SSSBs) with a wide electrochemical stability window and excellent stability against metallic sodium. However, its practical application is hindered by the instability of β ″ phase ( R m ) during sintering, low polycrystalline ionic conductivity at room temperature, and poor interfacial contact with sodium anodes. In this study, a stablized SSSB is obtained via doping Ga 3+ into Na 1.67 Mg 0.67 Al 10.33 O 17 (NMAO), which also suppresses the formation of the β ′ phase ( P 6 3 / mmc ) and decreases stacking faults. After sintering at 1550 °C for 2 h, Na 1.67 Mg 0.67 Al 9.33 GaO 17 (NMA9.33GO) exhibits an ionic conductivity of 9.2 × 10 −4 S cm −1 at 30 °C, ≈1.7 times greater than NMAO. Furthermore, Ga 3+ doping enhances the wettability with sodium, achieving superior contact stability and the formation of Na‐Ga alloys at the interface significantly improves electrode‐electrolyte contact stability, achieving a high critical current density (CCD) of 0.8 mA cm −2 and a low interfacial impedance of 16 Ω cm 2 . A quasi‐solid‐state battery assembled with Na 3 V 2 (PO 4 ) 3 (NVP) as the cathode demonstrates excellent cycling stability and rate performance, retaining a high discharge capacity of 91 mAh g −1 at 5 C, and maintaining 87% capacity retention after 1000 cycles at 1 C. This work provides new insights into improving electrolyte performance and interfacial engineering ...