Polypyrrole/Al2O3/LiMn2O4 cathode for enhanced storage of Li ions

LiMn 2 O 4 (LMO) is a promising cathode material for the assembly of lithium ion batteries in that it satisfies the requirement for a high specific capacity, but it lacks structural stability during long-term cycling. To overcome this challenge, Al 2 O 3 and PPy are coated onto LiMn 2 O 4 (PPy/Al 2 O 3 /LMO) using a sol–gel method followed by oxidative chemical polymerization. The discharge capacity of PPy/Al 2 O 3 /LMO reaches 121.73 mAh g −1 at a rate of 1C. The retention is as high as 95.81% even after 100 charge/discharge cycles. The enhanced performance of PPy/Al 2 O 3 /LMO for Li ion storage results from improved electron conductivity, a more rapid ion migration rate, and reduced Mn ion dissolution. This strategy could be further utilized for the synthesis of other cathode materials for use in lithium ion batteries.