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 Na_0.67Ni_0.23Mg_0.1Mn_0.67O₂ |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.