Processable Potassium Metal Anode for Stable Batteries

• Published in: Energy & environmental materials (Hoboken, N.J.) N.J.), 2022-10, Vol.5 (4), p.1278-1284
• Main Authors: Wei, Zhenghang, Wang, Aoxuan, Guan, Xuze, Li, Guojie, Yang, Zhiwei, Huang, Chengde, Zhang, Jing, Ren, Libin, Luo, Jiayan, Liu, Xingjiang
• Format: Article
• Language: English
• Subjects: Anodes; Batteries; Composite materials; Dendritic structure; Electrochemical analysis; Electrochemistry; Electrodes; Energy storage; Graphene; High temperature; K metal anode; K metal battery; Lithium; Lithium-ion batteries; Melting point; Melting points; Metals; Pigments; Potassium; processibility; Rechargeable batteries; Redox potential; reduced graphene oxide; stability; Storage batteries; Storage systems
• ISSN: 2575-0356; 2575-0348; 2575-0356
• DOI: 10.1002/eem2.12244

The future of high‐energy density electrochemical energy storage systems relies on the advancement of rechargeable batteries that utilize reactive metals as anodes. In the alkaline metal, secondary battery systems because of abundant resource, high capacity and low redox potential, potassium (K) metal secondary battery (KMB) is expected to replace the existing lithium‐ion battery as a versatile platform for high‐energy density, cost‐effective energy storage devices. However, the difficulty in processing metal K results in nonstandard electrodes and hinders the development of KMBs. Furthermore, the mobility of the K metal anode due to its unique low‐melting point character at elevated temperatures in practical conditions leads to severe instability and risks in chemical/electrochemical processes. Herein, we fabricate a processable and moldable composite K metal anode by encapsulating K into reduced graphene oxide (rGO). The composite electrode can be engineered into various shapes discretionarily with precise sizes and stabilize the K metal anode at relatively high temperatures. Remarkably, the composite anode exhibits excellent cycling performance at high current density (8 mA cm−2) with dendrite‐free morphology. Paired with a Prussian blue cathode, the rGO–K composite anode shows much improved electrochemical performance and extended lifetime. The difficulty in processability, low melting point, and inherent instability has greatly hindered the practical applications of KMBs. Herein, we fabricate a processable composite K metal anode by encapsulating K into lightweight reduced graphene oxide, which solves the liquidity problem of low‐melting point K metal at relatively high temperature during the practical battery cycling process. The composite anode exhibits excellent cycling performance and low overpotential with dendrite‐free morphology.