Electrochemical behavior of Sn-doped Li1.2V3O8 cathode materials for Lithium-ion batteries

• The Sn 4+ doping can improve the purity and crystallization properties of Li 1.2 V 3 O 8 . • The Sn 4+ doping can increase the interlayer distance of Li 1.2 V 3 O 8 . • The Sn 4+ doping can improve the electrochemical reactivity of vanadium in Li 1.2 V 3 O 8. • The electrochemical properties of Li 1.2 V 2.97 Sn 0.03 O 8 were improved. The discharge capacity of Li 1.2 V 3 O 8 is obviously decreased, and the diffusion coefficient of lithium ion is relatively low. In order to improve the electrochemical performances of Li 1.2 V 3 O 8 , the study of Sn 4+ doped Li 1.2 V 3 O 8 is performed. The initial discharge capacity of Li 1.2 V 2.97 Sn 0.03 O 8 is lower than that of Li 1.2 V 3 O 8 . However, the discharge capacity of Li 1.2 V 2.97 Sn 0.03 O 8 is higher than that of Li 1.2 V 3 O 8 from the second cycle, and the discharge capacity of Li 1.2 V 2.97 Sn 0.03 O 8 are significantly improved at high current density. At 50, 100 and 200 mA g −1 , the discharge capacities of Li 1.2 V 2.97 Sn 0.03 O 8 are 271.8, 268 and 257.2 mAh g −1 , respectively. The discharge capacity is maintained at 264.7, 259.6 and 238.3 mAh g −1 , after 50 cycles at room temperature. Furthermore, the electrochemical reactivity of vanadium in Li 1.2 V 3 O 8 electrodes could be improved by Sn 4+ doping. Thus, the electrochemical reaction kinetics and the electrochemical properties of Li 1.2 V 2.97 Sn 0.03 O 8 are improved.