KVPO4F and KVOPO4 toward 4 volt-class potassium-ion batteries

Kuniko Chihara; Akihiro Katogi; Kei Kubota; Shinichi Komaba

doi:10.1039/c6cc10280h

KVPO₄F and KVOPO₄ toward 4 volt-class potassium-ion batteries

Chem Commun (Camb). 2017 May 4;53(37):5208-5211. doi: 10.1039/c6cc10280h.

Authors

Kuniko Chihara¹, Akihiro Katogi, Kei Kubota, Shinichi Komaba

Affiliation

¹ Department of Applied Chemistry, Tokyo University of Science, Shinjuku, Tokyo 162-8601, Japan. komaba@rs.kagu.tus.ac.jp.

PMID: 28443861
DOI: 10.1039/c6cc10280h

Abstract

Structurally identical KVPO₄F and KVOPO₄ are evaluated as positive electrode materials for non-aqueous potassium-ion batteries. KVPO₄F and KVOPO₄ show highly reversible potassium extraction/insertion with discharge capacities of ca. 92 mA h g^-1 and ca. 84 mA h g^-1, respectively, and their average discharge voltage reaches above 4.0 V with 1 M KPF₆ EC/PC electrolyte at 2.0-5.0 V. Despite the extraction of large potassium-ions, their lattice volume shrinkages after charging to 5.0 V are 5.8% for KVPO₄F and 3.3% for KVOPO₄, leading to stable cycle performance. This is the first report to confirm the charge/discharge behaviours of vanadium phosphate electrodes in 4 V-class K cells.