Durable Sodium Battery with a Flexible Na3Zr2Si2PO12–PVDF–HFP Composite Electrolyte and Sodium/Carbon Cloth Anode

High-performance electrolytes and electrode materials play a critical role in advanced sodium-ion batteries with higher energy densities. In this work, we prepared a poly(methyl methacrylate)-filled composite electrolyte (named as GHSE) by in situ polymerization of methyl methacrylate in the porous Na3Zr2Si2PO12–polymer vinylidene fluoride–hexafluoropropylene composite membrane for the first time. The GHSE membrane exhibits a high ionic conductivity (2.78 × 10–3 S cm–1), wide electrochemical window (∼4.9 V), high Na+ ion transference number (∼0.63), good thermal stability and flexibility, as well as smaller interfacial resistance. Moreover, a composite Na/C anode was prepared, which shows good dendrite suppression ability. The full cell Na0.67Ni0.23Mg0.1Mn0.67O2 |GHSE|Na/C exhibits excellent rate capability with an initial discharge capacity of 96 mAh g–1 even at a higher current density of 192 mA g–1 and excellent cyclability for 600 cycles. These results suggest that the GHSE and Na/C anode are promising electrolyte and anode materials for Na-ion batteries, respectively.