Aqueous Lithium-Ion Batteries Using Polyimide-Activated Carbon Composites Anode and Spinel LiMn2O4 Cathode

Polyimide/activated carbon (PI/AC) composites were prepared by in situ polymerization of 1,4,5,8-naphthalenete-tracarboxylic dianhydride (NTCDA) and ethylene diamine (EDA) on activated carbon with various mass ratios varying from 50:50 to 70:30. These composites were examined as anode materials in 5 M LiNO 3 solution in the potential window from −0.75 to 0 V vs Ag/AgCl. With an optimal composition PI/AC 50:50 in mass ratio, the composite delivers a specific capacity of 87 mAh g –1 at a current density of 0.2 A g –1, and it also shows excellent cycling stability and rate capability. A sealed full cell containing a PI/AC composite anode and LiMn 2 O 4 cathode delivers a specific capacity of 42 mAh g –1 and energy density of 51Wh kg 1– (based on the total weight of both active materials) at a current density of 0.2 A g –1 . The full cell exhibits good cycling stability with a specific capacity of 35 mAh g –1 after 450 cycles, corresponding to a capacity retention of 89%.