Organic 2,5-dihydroxy-1,4-benzoquinone potassium salt with ultrahigh initial coulombic efficiency for potassium-ion batteries.

Here, we propose a new organic 2,5-dihydroxy-1,4-benzoquinone potassium salt (K2C6H2O4) endowing an ultrahigh initial coulombic efficiency of 96% as an advanced anode for potassium-ion batteries. Theoretical calculations and experimental results suggest that K+ can reversibly insert into this organic compound due to the flexible and stable structure of the K2C6H2O4 molecule as well as fast K+ kinetics in the selected dimethyl ether-based electrolyte.