Current Status and Challenges of Calcium Metal Batteries

Abstract

Ca-metal batteries, one of the promising advanced energy storage devices, have received significant development in the last few years. However, challenges still exist in efficient and cost-effective Ca-metal utilization, fast Ca-ion transport and diffusion, and high energy density and stable-cycling Ca-storage. Herein, by cross-checking most relevant literature reported previously, an intuitive depiction for state-of-the-art Ca-metal batteries, including collectors, electrolytes, and cathode materials, is presented from a voltage-capacity-efficiency's view, which facilitates reasonable comparisons from related fields. The performance of most cathode materials and calcium-metal electrodes in various electrolytes reported previously is comprehensively reviewed, as well as interphases and collectors. The strong and weak points of various electrolytes are discussed, and relevant challenges are pointed out. Recent breakthroughs in electrolyte and interphase engineering are emphasized. Finally, potential development directions for Ca-metal and electrolytes, as well as some future prospects for cathode materials, are rationally predicted.