Revisit of Polyaniline as a High-Capacity Organic Cathode Material for Li-Ion Batteries

Polyaniline (PANI) has long been explored as a promising organic cathode for Li-ion batteries. However, its poor electrochemical utilization and cycling instability cast doubt on its potential for practical applications. In this work, we revisit the electrochemical performance of PANI in nonaqueous electrolytes, and reveal an unprecedented reversible capacity of 197.2 mAh g^-1 (244.8 F g^-1) when cycled in a wide potential range of 1.5 to 4.4 V vs. Li⁺/Li. This ultra-high capacity derives from 70% -NH- transformed to =NH⁺- during deep charging/discharging process. This material also demonstrates a high average coulombic efficiency of 98%, an excellent rate performance with 73.5 mAh g^-1 at 1800 mA g^-1, and retains 76% of initial value after 100 cycles, which are among the best reported values for PANI electrodes in battery applications.