Effect of lithium or aluminum substitution on the characteristics of graphite for anode of lithium ion batteries

摘要

Modification of graphite for anode of lithium ion batteries is investigated. Results of X-ray diffraction shows lithium and aluminum exists as Li compound (CH3COOLi@2H2O) and Al compound (AlD3) in the graphite, respectiovely.The Bmnauer-Emmer-Teller (BET) surface area of the modified graphite increases. According to the electrochemical measurements of Li/C cell and prototype Li-ion batteries, the Li-doped graphite has large reversible capacity of 312.2mA@h/g, low irreversible capacity of 52.9 mA@h/g, and high initial coulombic efficiency of 85.51%. The 063448 size prototype battery with Li-doped graphite anode has large discharge capacity of 845 mA@h and good cycling performance. The initial charge/discharge characteristic of Al-doped graphite is close to those of undoped graphite, but the prototype battery with Al-doped anode shows the best cycling performance with capacity retention ratio of 94.06% at the 200th cycle.