A ceramic/polymer composite solid electrolyte for sodium batteries

Abstract

Achieving high ionic conductivity in solid electrolytes and reducing the interfacial resistance between solid electrolytes and electrode materials are considered to be one of the biggest challenges in developing solid-state batteries. The integration of the high ionic conductivity of inorganic ceramics and the flexibility of organic polymers was attempted to yield a solvent-free ceramic/polymer composite solid electrolyte for Na batteries for the first time. The composite solid electrolytes exhibit a Na⁺ ion conductivity as high as 2.4 mS cm⁻¹ at 80 °C. Meanwhile, this composite membrane is thermally stable up to 150 °C and maintains the flexibility of polymer electrolytes. The solid-state Na₃V₂(PO₄)₃/CPE/Na battery using this ceramic/polymer composite electrolyte exhibits an initial reversible capacity of 106.1 mA h g⁻¹ and excellent cycle performance with negligible capacity loss over 120 cycles.