摘要
Developing cost-effective and reliable solid-state sodium batteries with superior performance is crucial for stationary energy storage.A key component in facilitating their application is a solid-state electrolyte with high conductivity and stability.Herein,we employed aliovalent cation substitution to enhance ionic conductivity while preserving the crystal structure.Optimized substitution of Y^(3+)with Zr^(4+)in Na_(5)YSi_(4)O_(12) introduced Naþion vacancies,resulting in high bulk and total conductivities of up to 6.5 and 3.3 mS cm^(-1),respectively,at room temperature with the composition Na_(4.92)Y_(0.92)Zr_(0.08)Si_(4)O_(12)(NYZS).NYZS shows exceptional electrochemical stability(up to 10 V vs.Naþ/Na),favorable interfacial compatibility with Na,and an excellent critical current density of 2.4 mA cm^(-2).The enhanced conductivity of Naþions in NYZS was elucidated using solid-state nuclear magnetic resonance techniques and theoretical simulations,revealing two migration routes facilitated by the synergistic effect of increased Naþion vacancies and improved chemical environment due to Zr^(4+)substitution.NYZS extends the list of suitable solid-state electrolytes and enables the facile synthesis of stable,low-cost Naþion silicate electrolytes.
基金
the China Scholarship Council (CSC,Grant Nos.201906200023,201906200016 and 201808080137,respectively)for financial support
funding from the European Union's Horizon 2020 research,innovation program under the Marie Sklodowska-Curie grant agreement (No.101034329)
the WINNING Normandy Program supported by the Normandy Region,France.
