Self-assembled α-MnO2 urchin-like microspheres as a high-performance cathode for aqueous Zn-ion batteries

• Published in: Science China materials Vol. 63; no. 7; pp. 1196 - 1204
• Main Authors: Wu, Yunzhao, Tao, Ye, Zhang, Xianfu, Zhang, Kai, Chen, Shengbin, Liu, Yu, Ding, Yong, Cai, Molang, Liu, Xuepeng, Dai, Songyuan
• Format: Journal Article
• Language: English
• Published: Beijing Science China Press 01.07.2020; Springer Nature B.V
• Subjects: Cathodes; Chemistry and Materials Science; Chemistry/Food Science; Clean energy; Diffusion rate; Electric vehicles; Electrochemical analysis; Electrode materials; Energy storage; Flux density; Ion diffusion; Lithium; Manganese dioxide; Materials Science; Microspheres; Morphology; Nanofibers; Rechargeable batteries; Self-assembly; Zn; reversible phase evolution; α-MnO; synergistic H; urchin-like microspheres; insertion/extraction; aqueous Zn-ion batteries; fast ion diffusion coefficients
• ISSN: 2095-8226; 2199-4501
• DOI: 10.1007/s40843-020-1293-8

Aqueous Zn-ion batteries (AZIBs) are one of the promising battery technologies for the green energy storage and electric vehicles. As one attractive cathode material for AZIBs, α-MnO 2 materials exhibit superior electrochemical properties. However, their long-term reversibility is still in great suspense. Considering the decisive effect of the structure and morphology on the α-MnO 2 materials, hierarchical α-MnO 2 materials would be promising to improve the cycle performance of AZIB. Here, we synthesized the α-MnO 2 urchin-like microspheres (AUM) via a self-assembled method. The porous microspheres composed of one-dimensional α-MnO 2 nanofibers with high crystallinity, which improved the surface area and active sites for Zn 2+ intercalation. The AUM-based AZIB realized a high initial capacity of 308.0 mA h g −1 and the highest energy density was 396.7 W h kg −1 The kinetics investigation confirmed the high capacitive contribution and fast ion diffusion of the AUM. Ex-situ XRD measurement further verified the synergistic insertion/extraction of H + and Zn 2+ ions during the charge/discharge process. The superiority of the AUM guaranteed good electrochemical performance and reversible phase evolution, and this application would promote the follow-up research on the advanced AZIB.