Failure analysis with a focus on thermal aspect towards developing safer Na-ion batteries
Li Yuqi1, 2, Lu Yaxiang1, 3, †, Chen Liquan1, 2, 3, Hu Yong-Sheng1, 2, 3, ‡
       

(a) DSC heating curves up to 350 °C of solvents alone, solvent mixtures,propylene carbonate (PC) based electrolytes with 1 M of various Na salts, and ethylene carbonate (EC): diethyl carbonate (DEC) solvent mixture with or without a sodium salt (1 M NaClO4).[32] (b) TG curves of the NaPF6/PC electrolyte and the NaPF6/BMITFSI electrolytes range from room temperature to 600 °C.[36] (inset: the chemical structures of the cation and anion components of BMITFSI) (c) Left: Weight loss of laboratory-made NaFSA (NaFSI)/TMP electrolytes and conventional 1.0 M NaPF6/EC:DEC (1 : 1 vol.%) electrolyte in the thermogravimetric test. Right: flame tests of laboratory-made 3.3 M NaFSA/TMP electrolyte and conventional 1.0 M NaPF6/EC:DEC (1 : 1 vol.%) electrolyte.[39] (d) Schematic illustration of the SEI layer and possible mechanism for the decomposition of the TFEP-derived interlayer. (e) Cycling performance at 100 mA/g of the hard carbon/Na3V2(PO4)3 full cell.[41]