Cellulose/lignin-based carbon nanobelt aerogels coating on VSe2 nanosheets as anode for high performance potassium-ion batteries

Abstract

Potassium-ion batteries (PIBs) have attracted high attention in recent years due to the low cost, low redox potential and abundant naturally storage. However, PIBs has been hampered by the large K+ ion and huge volumetric change, which lead to the poor electrochemical kinetic and cycling performance. Herein, the cellulose/lignin-based carbon nanobelt aerogels coating on VSe2 nanosheets (VSe2@CNB) as anode materials for PIBs has been fabricated for the first time by the selenization of VO(acac)2 and subsequent polymerization and coating by carbon nanobelt aerogels. The enhancing in the conductivity and the structural protection have been provided by the interlinked, high surface area and porosity carbon nanobelt aerogels, the VSe2@CNB shows improved potassium-storage performance, obtains high reversible capacity of 227.4 mAhg−1 at 100 mAg−1 after 100 cycles, as well as delivering long-term cycling stability of 125 mAhg−1 at 500 mAg−1 after 1000 cycles with high columbic efficiency (99%). Ex situ X-ray diffraction (XRD) and transmission electron microscope (TEM) measurement indicate that the reversible phase evolution for the storage potassium mechanism of the VSe2@CNB composite consists of K+ insertion into the layer of VSe2 nanosheets and conversion reaction of VSe2 transfer into K2Se.