Facile synthesis of nano-Ag decorated Nb2O5 on the 3D graphene framework for high-performance lithium storage

Abstract

Niobium-oxide based materials are well-known in electrochemical energy area because of their unique structural advantage, which can realize fast ion insertion/extraction and interfacial pseudo-capacitance effects. However, instinct poor electrical conductivity and terrible volume change of Nb2O5 under lithiation/delithiation have hindered its practical application. Here, a three-dimensional (3D) graphene network has been constructed by a simple hydrothermal reaction and utilized to buffer the severe structural variation of Nb2O5. Meanwhile, silver nanoparticles have been incorporated into this 3D structure through silver-mirror reaction, by which the charge-transfer ability of the composite (Ag-Nb2O5@rGO) can be significantly improved. The obtained Ag-Nb2O5@rGO can contribute a charge capacity of ∼ 208.0 mAh/g at 0.5C and ∼ 106.6 mAh/g up to 20C. Meanwhile, superior cyclic performance with ∼ 80 % capacity retention after 500 cycles at 2.5C can be achieved. This demonstrates that the Ag-Nb2O5@rGO composite can work as a high-performance anode for electrochemical energy devices.