A comprehensive study on the electrolyte, anode and cathode for developing commercial type non-flammable sodium-ion battery

Abstract

Here, we present a comprehensive study of choice of electrolyte, anode and cathode to develop commercially viable non-flammable sodium-ion battery. We report hard carbon (HC) vs. Na using ether-based non-flammable electrolyte (1 ​M NaBF4 in tetraglyme) and compare storage performance, thermal stability and SEI formation with those obtained using carbonate-based electrolyte (1 ​M NaClO4 in EC:PC = 1:1 v/v). The results shows that 1 ​M NaBF4 in tetraglyme works as a better electrolyte than carbonate-based electrolyte for HC anode. We present and compare storage performances of pristine and aliovalent-doped Na3V2(PO4)3 (NVP) vs. Na. Doped-NVP outperforms pristine cathode in terms of specific capacity and rate capability. 18650-type non-flammable sodium-ion cells fabricated using modified NVP vs. HC exhibits energy density of 60 ​Wh kg−1. When discharged at a high rate close to 5C, the cell successfully retains 83% of its storage capacity obtained at low rate. When cycled at C/5, doped NVP vs. HC 18650 ​cell retains 90% of its initial capacity after 200 cycles.