摘要
The development of high-capacity and high-rate anodes has become an attractive endeavor for achieving high energy and power densities in lithium-ion batteries(LIBs).Herein,a new-type anode material of reduced graphene oxide(rGO) supported niobium oxyphosphate(NbOPO_4) nanosheet assembled twodimensional composite material(NbOPO_4/rGO) is firstly fabricated and presented as a promising highperformance LIB anode material.In-depth electrochemical analyses and in/ex situ characterizations reveal that the intercalation-conversion reaction takes place during the first discharge process,followed by the reversible redox process between amorphous NbPO_4 and Nb which contributes to the reversible capacity in the subsequent cycles.Meanwhile,the lithiation-generated Li3 PO_4,behaving as a good lithium ion conductor,facilitates ion transport.The rGO support further regulates the structural and electron/ion transfer properties of NbOPO_4/rGO composite compared to neat NbOPO_4, resulting in greatly enhanced electrochemical performances.As a result,NbOPO_4/rGO as a new-type LIB anode material achieves a high capacity of 502.5 mAh g^(-1) after 800 cycles and outstanding rate capability of 308.4 mAh g^(-1) at 8 A g^(-1).This work paves the way for the deep understanding and exploration of phosphate-ba sed high-efficiency anode materials for LIBs.
基金
supported by the National Natural Science Foundation of China (21805219, 51832004, 51521001)
the National Key Research and Development Program of China (2016YFA0202603)
the Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHT2020-003)
the Programme of Introducing Talents of Discipline to Universities (B17034)
the Yellow Crane Talent (Science & Technology) Program of Wuhan City。
