Cathodic polarization suppressed sodium-ion full cell with a 3.3 V high-voltage

The application of sodium-ion batteries (SIBs) is largely depended on the high energy density electrode system since it suffers from intrinsic high voltage of Na (0.33 V vs. Li). To overcome these limitations, we propose a high-voltage sodium-ion full cell via cathodic polarization suppression. NASICON structured Na3V2(PO4)3 (NVP) cathode and poorly-graphitized hard carbon (HC) anode are synthesized as the targeted materials through an easily scalable coprecipitation method and a simple biomass-directed technique, respectively. Through morphologic optimization and carbon decoration, the NVP half cell demonstrates a high output voltage of 3.4 V, ultralong cyclability (over 4000 cycles) and distinguished rate capability (77 mA h g−1 at 150 C), which is attributed to the enhanced electrical transport behaviors and carrier transmission dynamics. When extended to NVP//HC, the overpotential has been successfully restrained, and the full cell exhibits a theoretical average voltage of 3.3 V, which shows substantial increases in the energy density (>20%) compared to bulk and bare NVP based full cell. The prototype design of high-energy and low-cost sodium-ion full cell in this work opens the door for accelerating the development and application of SIBs.