Superior potassium storage behavior of hard carbon facilitated by ether-based electrolyte

Hard carbon is a promising anode material for potassium ion batteries, because of its abundant resource, low price and excellent electrochemical performance. Electrolyte, plays important role in determining the storage performance of electrode materials for alkaline metal based batteries, yet there is no report on how the solvents of the electrolyte impacts the potassium storage behavior of hard carbon. In this study, hard carbon prepared with corn cob as precursor (denoted as CCHC) was investigated in both ester and ether electrolytes. CCHC exhibits superior potassium storage performance in ether electrolyte than in ester electrolyte, in terms of capacity, rate and cycle performance. CCHC electrode presents different galvanostatic charge-discharge and CV profiles in ether and ester electrolytes. Kinetic studies and X-ray photoelectron spectra analyses suggest that the superior potassium storage behavior of CCHC in ether electrolyte would be attributed to larger capacitive storage contribution, favorable solid electrolyte interphase (SEI) film. This study would benefit to explore the potassium storage feasibility of hard carbon and achieve better understanding of alkaline metal storage mechanisms in carbon materials with different electrolytes.