Takashi Hibino

Improved LiMn2O4/Graphite Li-Ion Cells at 55°C

Sodium phosphate additives and mixed electrolytes of Li(C 2 F S SO 2 ) 2 N (LiBETI) and LiPF 6 were examined to improve cycle performances of Li 1.04 Mn 1.96 O 4 /graphite cells at high temperatures. The cycle performance of those cells exceeded 80% at 100 cycles at 55°C in an optimum combination of a 0.975 M LiBETI and 0.025 M LiPF 6 /ethylene carbonate (EC):dimethylcarbonate (DMC) (1:2) electrolyte solution containing 5% of Na 4 P 2 O 7 or 5% of Na 5 P 3 O 10 additive. Such a cycle performance is considered to fulfill the requirement for practical use.