CN(CH2)2Si(CH3)(OCH2CH2OCH3)2 (BNS) is used as electrolyte solvent to improve the safety for LiNi1/3Co1/3Mn1/3O2 (NCM)/graphite battery. BNS increases the thermal stability of the carbonate-based electrolyte with (de) lithiated cathode/anode and the electrochemical stability of coin cells. By using an optimal BNS-based electrolyte formula, 13 Ah NCM/graphite prismatic cell achieves 95.8% retain of capacity at 2 C/3 C (charge/discharge) rate after 600 cycles. Meanwhile, 13 Ah prismatic cell exhibits improved safety performance in the nail penetration test.