Orthorhombic Nb2O5-x for Durable High-Rate Anode of Li-Ion Batteries

Zichao Liu; Wujie Dong; Jianbo Wang; Chenlong Dong; Yue Lin; I-Wei Chen; Fuqiang Huang

doi:10.1016/j.isci.2019.100767

Orthorhombic Nb₂O_5-x for Durable High-Rate Anode of Li-Ion Batteries

iScience. 2020 Jan 24;23(1):100767. doi: 10.1016/j.isci.2019.100767. Epub 2019 Dec 12.

Authors

Zichao Liu¹, Wujie Dong², Jianbo Wang¹, Chenlong Dong¹, Yue Lin³, I-Wei Chen⁴, Fuqiang Huang⁵

Affiliations

¹ State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China.
² State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
³ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
⁴ Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: iweichen@seas.upenn.edu.
⁵ State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China; State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China. Electronic address: huangfq@pku.edu.cn.

Abstract

Li₄Ti₅O₁₂ anode can operate at extraordinarily high rates and for a very long time, but it suffers from a relatively low capacity. This has motivated much research on Nb₂O₅ as an alternative. In this work, we present a scalable chemical processing strategy that maintains the size and morphology of nano-crystal precursor but systematically reconstitutes the unit cell composition, to build defect-rich porous orthorhombic Nb₂O_5-x with a high-rate capacity many times those of commercial anodes. The procedure includes etching, proton ion exchange, calcination, and reduction, and the resulting Nb₂O_5-x has a capacity of 253 mA h g^-1 at 0.5C, 187 mA h g^-1 at 25C, and 130 mA h g^-1 at 100C, with 93.3% of the 25C capacity remaining after cycling for 4,000 times. These values are much higher than those reported for Nb₂O₅ and Li₄Ti₅O₁₂, thanks to more available surface/sub-surface reaction sites and significantly improved fast ion and electron conductivity.

Keywords: Chemical Synthesis; Energy Materials; Energy Storage.