Non-Aqueous K-Ion Battery Based on Layered K 0.3 MnO 2 and Hard Carbon/Carbon Black

Abstract

Herein, we present the synthesis and characterization of negative (a hard carbon/carbon black composite) and positive (K 0.3 MnO 2) active materials for K-ion batteries as well as their combination in a non-aqueous K-ion cell. The hard carbon/carbon black composite can deliver up to 200 mAh g −1 while the layered birnessite K 0.3 MnO 2 delivers up to 136 mAh g −1 . The K-ion cell exhibits an interesting and encouraging cycling performance for 100 cycles. These exciting new insights demonstrate the potential of K-ion batteries, which are worth to be further investigated in greater detail. Since the 1970s, lithium-, sodium-and potassium-based recharge-able battery technologies have been studied in parallel. However, the commercialization of the first lithium-ion battery (LIB) in 1991 shifted the focus of the research community solely toward this battery tech-nology. Despite the success of LIBs, recent concerns about, e.g., the availability of lithium raw materials have led to an increased interest to revisit alternative secondary battery technologies. Attention shifted back to Na-ion batteries (NIBs) due to the high abundance and low cost of sodium minerals and the feasible replacement of the copper anode current collector with aluminum, which leads to a cheaper bat-tery. These advantages are considerable since NIBs show comparable electrochemical performance to LIBs.