Volume 8, Issue 1 1900796
Full Paper

Prepotassiated V2O5 as the Cathode Material for High-Voltage Potassium-Ion Batteries

Kai Yuan

Kai Yuan

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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Ruiqi Ning

Ruiqi Ning

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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Maohui Bai

Maohui Bai

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

School of Metallurgy and Environment, Central South University, Changsha, 410083 China

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Nan Hu

Nan Hu

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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Kun Zhang

Kun Zhang

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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Jinlei Gu

Jinlei Gu

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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Qingyu Li

Qingyu Li

Guangxi Key Laboratory of Low Carbon Energy Materials, School of Chemical and Pharmaceutical Science, Guangxi Normal University, Guilin, 541004 China

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Youguo Huang

Youguo Huang

Guangxi Key Laboratory of Low Carbon Energy Materials, School of Chemical and Pharmaceutical Science, Guangxi Normal University, Guilin, 541004 China

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Chao Shen

Corresponding Author

Chao Shen

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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Keyu Xie

Corresponding Author

Keyu Xie

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072 China

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First published: 01 October 2019
Citations: 33

Abstract

The voltage and capacity of cathodes are critical factors for energy density of batteries. However, the cutoff voltage of cathode materials in potassium-ion batteries (PIBs) is usually 4.0 V, causing structural transformations in the electrode materials in the course of repeated insertion/extraction of K+ ions with a large radius (1.38 Å). Materials with large interlayer spacing and short ion diffusion paths show promise to overcome this issue. K0.486V2O5 nanobelts, prepared by preinserting K+ ions into V2O5, are used as cathode materials in high-voltage PIBs. Various analysis methods are used to understand the insertion/extraction behavior of K+ ions in K0.486V2O5 cathodes cycled between 1.5 and 4.2 V. The analyses reveal the highly reversible structural evolution of K0.486V2O5, in which the chemically inserted K+ ions partially remain between VO layers charged at high voltage serving as stabilizing species to prevent phase transformations. K0.486V2O5 cathodes exhibit a high specific capacity of 159 mAh g−1 at 20 mA g−1 with good cycling stability of 67.4% after 100 cycles at 100 mAh g−1 in the half K-ion cell. The results provide guidelines for designing layered transition metal oxides to be used as cathode materials for high-voltage PIBs with high energy density.

Conflict of Interest

The authors declare no conflict of interest.

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