An insight into the initial Coulombic efficiency of carbon-based anode materials for potassium-ion batteries

Abstract

Potassium-ion batteries (KIBs), as one of the most promising alternatives to lithium-ion batteries (LIBs), are attracting increasing research interest due to the abundant resource of potassium and low cost. Although much effort has been devoted to improving the electrochemical performance, unfortunately, there are still many obstacles before it can be commercialized. Among them, the unsatisfactory initial Coulombic efficiency (ICE) of carbonaceous anodes greatly affects the full utilization of cathodes capacity in full cells. This review analyzes the formation mechanism of low ICE including inferior reversibility of potassiation/depotassiation process, the formation of solid electrolyte interface (SEI) film originates from decomposition of electrolyte, and so on. Meanwhile, key strategies are also summarized on how to improve low ICE, such as structural design, defects engineering, and binder/electrolyte optimization. More importantly, the recent progress, critical issues, challenges, and perspectives of ICE in KIBs are further discussed. This work provides an insight into the development of advanced carbon-based anode materials with high ICE for KIBs, and also offers a reference for the design of high-performance anode materials for other metal-ion batteries.