Double‐Sheet Vanadium Oxide as a Cathode Material for Calcium‐Ion Batteries
Munseok S. Chae, Jongwook W. Heo, Jooeun Hyoung, Seung‐Tae Hong
Abstract
Abstract Calcium‐ion batteries (CIBs) are theoretically considered one of the potential post‐lithium‐ion battery technologies. However, only a few host materials are known to intercalate Ca ions. Herein, we demonstrate the use of double‐sheet vanadium oxide V 2 O 5 ⋅ 0.63H 2 O as a high‐performance cathode material for CIBs. The vanadium oxide was synthesized via an electrochemical oxidation process on a graphite foil substrate. The material exhibited a high reversible capacity of 204 mAh g −1 at a 0.1 C rate in an aqueous electrolyte, with an average discharge voltage of 2.76 V vs. Ca/Ca 2+ , and a capacity retention of 86% after 350 cycles. The reaction mechanism can be described as a combination of diffusion‐controlled intercalation and surface‐limited pseudo‐capacitance reactions. This study provides a new type of Ca host material, motivating further development of new CIB cathode materials.