Abstract:
Spinel Li
1.05Ni
0.05Mn
1.90O
4 cathode material was synthesized via a flameless combustion method at 500 ℃ for 1 h followed by calcination at 600 ℃ for 3, 6, 9 and 12 h, respectively. Results show that Li−Ni co-doping material prepared at different secondary calcination time did not change the spinel structure of LiMn
2O
4. With the increased calcination time, the particle size was increased and the crystallinity was enhanced. At the secondary calcination time of 9 h, the obtained Li
1.05Ni
0.05Mn
1.90O
4 cathode material shows the particle size of 70—100 nm, and exhibits an excellent electrochemical performance with the first-discharge specific capacity of 94.8 mA·h·g
−1 and the capacity retention rate of 72.15% after 400 cycles at 1 C(1 C=148 mA·h·g
−1). Moreover, an initial discharge capacity of 89.7 mA·h·g
−1 with a capacity retention rate of 70.79% can be obtained after 800 cycles at 5 C. The optimized electrode has a low charge transfer resistance and apparent activation energy. The Li−Ni co-doping inhibits the Jahn-Teller effect effectively and alleviates Mn dissolution, hence, stabilizing the crystal structure and enhancing the rate capability and cycle performance.