Realizing anode-free potassium-organic batteries via sacrificial potassium superoxide additives

Equipped with an organic cathode and a bare anode current collector, the anode-free potassium-organic batteries present remarkable benefits in terms of reduced cost and elevated safety. However, it is challenging to realize such anode-free organic batteries, especially considering the complete absence of potassium ion (K + ) source preserved on both electrodes. Here, we have first introduced potassium superoxide (KO 2 ) as a preloaded sacrificial agent on an organic cathode, serving as an external K + supply in an initial anode-free potassium-organic cell architecture. It is shown that the unique solution-mediated decomposition mechanism of KO 2 endows its high compensation capacity of 368.9 mAh/g (97.9% of the theoretical value) and low decomposition overpotential of below 190 mV in the absence of additional conductive agents. Differential electrochemical mass spectrometry further confirms the single-electron transfer process for the KO 2 decomposition with minimal CO 2 evolution. A proposed chemical route for synthesizing high-purity KO 2 could further reduce its cost and enhance synthesis efficiency (typically in 5 minutes). The proof-of-concept of anode-free organic cell configuration is demonstrated with a decent lifespan (retaining 84.9 mAh/g after 300 cycles) and reversibility (average coulombic efficiency of 99.5%). The use of KO 2 -based cathode additives offers an effective route to address the initial K + deficiency and enhances the electrochemical performance of burgeoning potassium-organic batteries.