Unique CO2-modified VO2(B) nanosheets for lithium batteries with high electrochemical performance

摘要

Heteroatom doping has always been a common modification method for lithium-ion batteries (LIBs) cathodes. The addition of guest heteroatoms to the material can adjust the microstructure of the host material, and enlarge the lattice spacing or form the vacancy defect of oxygen, which can effectively im-prove the Electrochemical performance of materials. Herein, CO2-modified VO2(B) nanorods were syn-thesized via a simple one-step hydrothermal method. Thanks to the extended layer spacing in VO2(B) that results from CO2 small molecules, the synthesized CO2-VO2 electrode exhibits a high initial capacity of 251.1 mA g-1 at 100 mA g-1, and a capacity retention of 81.8 % after 80 cycles. It is worth noting that the CO2- VO2 electrode also has a high rate capacity (170.0 mAh g-1 at 1 A g-1), and the capacity recovery rate can reach 84.5 % even under the condition of variable current. Further studies showed that the role of CO2 small molecules as a pillar in the interlayer of VO2(B) and a weak electrostatic attraction between OCO2 and Li+ existed, resulting in a robust crystal structure and convenient Li-ion diffusion conditions during the (de) intercalation of lithium ions in VO2(B). This study opens the way for further exploration of the application of small molecule doping in the field of lithium-ion batteries.

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