An alkali metal secondary electrochemical cell, and preferably a lithium ion cell, activated with a quaternary solvent system, is described. The solvent system comprises a quaternary mixture of dialkyl carbonates and cyclic carbonates, and preferably dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate and ethylene carbonate. Lithium ion cells activated with this electrolyte have good room temperature cycling characteristics and excellent low temperature discharge behavior.