Electro-activation to achieve entropy increase of organic cathode for potassium-ion batteries

Developing highly stable cathode materials is the key to achieving long-life K-ion batteries (KIBs). Considering that cathode with higher entropy can promote the ion adsorption process, we developed a method with heat treatment and synergistic electro-activation of 3,4,9,10-perylene-tetracarboxylic dianhydride (EA-PTCDA) to realize entropy increase in PTCDA, which achieves a stable K-ion storage. From our characterization results, the molecular stacking structure of EA-PTCDA and the C–O and C–H bending vibration at the edge position of PTCDA molecules decreased after electro-activation, indicating the achievement of entropy increase in the EA-PTCDA cathode. After treatment, our EA-PTCDA exhibits a high discharge capacity of 92 mA h g−1 after 100 cycles at 20 mA g−1 for KIBs. Even at a high current density of 200 mA g−1, our EA-PTCDA also maintains a discharge specific capacity of 66 mA h g−1 after 1000 cycles, showing shallow capacity decay. We believe that our method of achieving entropy increase in cathode materials based on electro-activation provides a reference for achieving high-performance KIBs.