Coral-Like Hierarchical Nanostructured ZnMn <sub>2</sub> O <sub>4</sub> /Mn <sub>2</sub> O <sub>3</sub> Composites Synthesized by Zinc-Absent Method as a High-Performance Cathode Material for Aqueous Zinc-Ion Batteries
Kexing Cai, Shaohua Luo, Jun Cong, Kun Li, Shengxue Yan, Pengqing Hou, Qing Wang, Yahui Zhang, Xin Liu
Abstract
As one of the multivalent ion batteries, the zinc ion battery has the advantages of high-volume energy density and good safety. In this paper, coral-like and nanoparticle crosslinking hierarchical nanostructured ZnMn 2 O 4 /Mn 2 O 3 composites were successfully synthesized as cathode materials for zinc ion batteries by a simple sol-gel combined with the zinc-absent method. ZnMn 2 O 4 /Mn 2 O 3 composites with good properties were prepared when the zinc content was 10%. The prepared ZnMn 2 O 4 /Mn 2 O 3 composites have the morphology of coral-like and nanoparticle crosslinking and uniform particle size distribution. Compared with pure ZnMn 2 O 4 and Mn 2 O 3 , the composites show excellent electrochemical properties. Using 0.5 M Zn(CF 3 SO 3 ) 2 -AN/H 2 O (8:2) as the electrolyte, the first discharge capacity of the material can reach 170.7 mAh·g −1 at 0.05 C. After 150 cycles, the discharge capacity remained 109 mAh·g −1 . The kinetic characteristic of the electrode was studied by the galvanostatic intermittent titration technique, and the electrochemical reaction mechanism was studied by ex situ XRD. It was found that the two-phase recombination improved the diffusion rate of Zn 2+ . In the field of aqueous zinc ion batteries, an effective modification idea is provided for the research of spinel ZnMn 2 O 4 cathode material with low specific capacity.