Hollow-Sphere-Structured Na4Fe3(PO4)2(P2O7)/C as a Cathode Material for Sodium-Ion Batteries

Li-Ming Zhang; Xiao-Dong He; Shuo Wang; Nai-Qing Ren; Jun-Ru Wang; Jie-Min Dong; Fei Chen; Yi-Xuan Li; Zhao-Yin Wen; Chun-Hua Chen

doi:10.1021/acsami.1c04035

Hollow-Sphere-Structured Na₄Fe₃(PO₄)₂(P₂O₇)/C as a Cathode Material for Sodium-Ion Batteries

ACS Appl Mater Interfaces. 2021 Jun 9;13(22):25972-25980. doi: 10.1021/acsami.1c04035. Epub 2021 May 26.

Authors

Affiliations

¹ CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Key Laboratory of Energy Conversion Laboratory, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.

PMID: 34038077
DOI: 10.1021/acsami.1c04035

Abstract

The mixed polyanionic material Na₄Fe₃(PO₄)₂(P₂O₇) combines the advantages of NaFePO₄ and Na₂FeP₂O₇ in capacity, stability, and cost. Herein, we synthesized carbon-coated hollow-sphere-structured Na₄Fe₃(PO₄)₂(P₂O₇) powders by a scalable spray drying route. The optimal sample can deliver a high discharge capacity of 107.7 mA h g^-1 at 0.2C. It also delivers a capacity of 88 mA h g^-1 at 10C and a capacity of retention of 92% after 1500 cycles. Ex situ X-ray diffraction analysis indicates a slight volume change (less than 3%) in the Na₄Fe₃(PO₄)₂(P₂O₇) lattice cell. Therefore, such a spraying-derived carbon-coated Na₄Fe₃(PO₄)₂(P₂O₇) powder is a very attractive cathode electrode for sodium-ion batteries.

Keywords: cycling performance; full cell; hollow sphere; sodium iron phosphate; spray drying.