Effects of constant voltage at low potential on the formation of LiMnO2/graphite lithium ion battery

The effect of formation protocol including different constant voltage points at low potential, different constant voltage time, and different current were studied in this paper. The electrochemical impedance spectroscopy and stored and cycle performance tests were used to verify the parameter of different formation protocols. The results show that the resistance of solid electrolyte interphase film R _f drops during the whole potential range except 3.1 to 3.5 V and the diffusion coefficient P _f which represents the uniformity of anode electrode surface decreases only at this potential range. The effects of different constant voltage points at 3.1 to 3.5 V were studied to increase the uniformity of anode electrode surface and decrease the resistance of the SEI film. The film is more stable at 3.3 V constant voltage than other potentials, and a constant voltage 60 min is enough to form a uniformity and compact passivation layer. With the constant voltage time extending, the P _f decreases. When the formation current to constant potential is increased, the film is more loose (or porous) and less adhesive. The formation protocol of 0.01 C to 3.3 V constant voltage 60 min shows the best cycling performance, and formation protocol of no constant voltage shows the worst cycling performance. Considering the time and energy consumption, the formation protocol of 0.05 C to 3.3-V constant voltage 60 min is the best.