Lithiated Mo4O11 to improve excellent cycle stability of MoO2 nanoparticles for lithium-ion battery

Abstract MoO2/Mo4O11 composites were obtained by annealing (NH4)8Mo10O34 products. And MoO2 nanoparticles were prepared by using urea as a reducing agent to reduce Mo4O11 in MoO2/Mo4O11 composites. When tested as anode materials of lithium-ion batteries, the reaction type of MoO2 nanoparticles is mainly intercalation reaction (MoO2 + xLi ↔ LixMoO2) in initial charging/discharging cycles and after that gradually transforms into a conversion reaction (LixMoO2 + xLi ↔ Mo + xLi2O). However, for MoO2/Mo4O11 composites, due to the existence of Mo4O11 phase, intercalation reaction of MoO2 can rapidly transform into conversion reaction after a complete cycle. As a result, the MoO2/Mo4O11 composites present a high initial discharge capacity of 1,113 mAh g−1 and reversible specific capacity of 400 mAh g−1 after 100 cycles at 100 mA g−1. Comparatively, the MoO2 electrode delivers 300 mAh g−1 in the same condition. The excellent cycling performance of MoO2/Mo4O11 composites can be attributed to the rapid transformation of reaction types averting a structural collapse of electrode materials. This research may serve as an enlightenment for improving the cycle stability of other materials as the anode of lithium ion batteries.