Effect of SO2 and CO2 additives on the cycle performances of commercial lithium-ion batteries

The effects of SO2 and CO2 additives in electrolytes on the cycle properties of liquid-state Al-plastic film lithium-ion batteries were first investigated. The experimental electrolytes were added with different amounts of SO2 and CO2. The baseline electrolyte was 1 mol L-1 LiPF6 in ethylene carbonate/dimethylcarbonate/ethyl-methyl carbonate (1: 1: 1, by volume), and graphite was used as anode. The main analysis tools were cycling test, rate capability, internal resistance test, low-temperature performance, and thermal stability. The results showed that both of the additives could promote to form an excellent solid electrolyte interface film on the surface of graphite anode, leading to excellent cycle performances, the capacity retentions of CO2 and S5 were 94% and 97% after 400 cycles, respectively. Besides, the results also exhibited that the electrochemical performances of internal resistance, rate capability, low-temperature performance, and thermal stability were not changed significantly by the use of SO2 and CO2 as electrolyte additives.