Investigation of Ca Insertion into α-MoO<sub>3</sub> Nanoparticles for High Capacity Ca-Ion Cathodes
Sang-Hyeon Kim, Liang Yin, Seong‐Min Bak, Timothy T. Fister, Haesun Park, Prakash Parajuli, Jihyeon Gim, Zhenzhen Yang, Robert F. Klie, Peter Zapol, Yonghua Du, Saul H. Lapidus, John T. Vaughey
Abstract
Calcium-ion batteries (CIBs) are a promising alternative to lithium-ion batteries (LIBs) due to the low redox potential of calcium metal and high abundance of calcium compounds. Due to its layered structure, α-MoO3 is regarded as a promising cathode host lattice. While studies have reported that α-MoO3 can reversibly intercalate Ca ions, limited electrochemical activity has been noted, and its reaction mechanism remains unclear. Here, we re-examine Ca insertion into α-MoO3 nanoparticles with a goal to improve reaction kinetics and clarify the storage mechanism. The α-MoO3 electrodes demonstrated a specific capacity of 165 mA h g–1 centered near 2.7 V vs Ca2+/Ca, stable long-term cycling, and good rate performance at room temperature. This work demonstrates that, under the correct conditions, layered oxides can be a promising host material for CIBs and renews prospects for CIBs.