Functionalized Naphthalene Diimides as Low‐Cost Organic Cathodes for Potassium Batteries

Herein, the synthesis and investigation of two naphthalene diimide derivatives with the ethylenesulfonic (NDI1) and methylenecarboxylic (NDI2) groups appended to diimide nitrogen atoms in the form of potassium salts are reported. Synthesized compounds are characterized by 1H NMR, 13C NMR, and elemental analysis. Electrochemical performance of the diimides is evaluated in half‐cells with potassium anodes. Both materials show a decent specific capacity of 86–96 mAh g−1 at the first cycle at C/10 current rate in combination with average cell discharge potentials approaching 2.2 V. The obtained results suggest that synthesized materials can be considered as cheap electrode materials for potassium batteries designed for stationary energy storage applications.