Enhancement of the advanced Na storage performance of Na3V2(PO4)3 in a symmetric sodium full cell via a dual strategy design

Abstract

The exploration of advanced cathode materials with high electron conductivity and sodium-ion diffusion coefficient is of great significance for the further development of sodium-ion batteries. To improve the sodium-ion storage performance, herein, a dual strategy design involving the combination of a highly porous Na₃V₂(PO₄)₃ structure and a superior ionic/electronic conductive sulfur-doped carbon layer (HP-NVP@SC) is presented; a number of advantageous qualities, including large surface area, numerous active sites and a well-developed diffusion pathway, are exhibited by this composite. Notably, the HP-NVP@SC composite exhibits a superior rate performance (116.5 mA h g⁻¹ at 1C; 95 mA h g⁻¹ at 30C) and long-term cycling stability with 91% capacity retention after 2500 charge/discharge cycles at 20C. Specifically, the symmetric full cell assembled using the HP-NVP@SC composite as both a cathode and an anode also shows remarkable rate capability and notable cycling life with the high energy density of 164 W h kg⁻¹ at 1C. This dual strategy may inspire more research towards the construction of high-performance sodium-ion batteries.