Heteroatoms-doped carbon wrapped on T-Nb2O5 for high performance Mg-Li hybrid battery

Abstract

Mg-Li hybrid batteries (MLHBs) are regarded as promising candidates for electrical energy devices because they can combine the high capacity as well as fast ion transfer advantages of cathodes in lithium-ion batteries (LIBs) and the great safety feature of Mg metal anode in MLHBs. Here, we report a core-shell nanocomposite cathode material (T-Nb2O5 @C-PZS) for MLHB application, where heteroatoms-doped carbon layer is wrapped on T-Nb2O5 microparticles. Owning to the excellent pseudocapacitive performance from T-Nb2O5 core and the abundant N, S and P heteroatoms from the carbon shell, the T-Nb2O5 @C-PZS cathode shows a high discharge capacity (198 mAh g−1 at 0.1 A g−1), excellent rate performance (100 mAh g−1 at 2 A g−1) and outstanding cyclic stability (a capacity retention rate of 85% after 5000 cycles at 1.0 A g−1), when the Mg metal is used as the anode. The advantages of the preparation, microstructure as well as electrochemical performance of T-Nb2O5 @C-PZS make it a promising cathode for MLHBs.