Graphite Anode for a Potassium-Ion Battery with Unprecedented Performance.

Graphite as an anode for the potassium ion battery (PIBs) has the merits of low cost and potentially high energy density, while suffering from limited cycle time and inferior stability. Herein we, using a concentrated electrolyte, demonstrate that formation of a robust inorganic-rich passivation layer on the graphite anode could resolve these problems. Consequently, the PIBs with graphite anode could operate for over 2000 cycles (running time of over 17 months) with negligible capacity decay, and had a high area capacity over 7.36 mAh cm-2 with a high mass loading of 28.56 mg cm-2 . These unprecedented performances of graphite are comparable to that of traditional lithium-ion batteries, and may promote the rapidly development of high performance PIBs.