Polyoxometalate-based complex/graphene for high-rate lithium-ion batteries

Abstract The design and synthesis of new high-performance anode materials is greatly essential for the development of lithium ion batteries (LIBs). Herein, we propose an amorphous engineering strategy that the porous polyoxometalate-based complex {[Co4(L)2(HCOO)2(OH)2][SiO4(W3O9)4]}·6DMF·5H2O (Co-SiW) (L = resorcin Armand and Tarascon (2008) [4]arene-based methyl imidazole ligand) is anchored on the layered graphene oxide (GO) by ball-milling. The resulting composite materials, Co-SiW-B, Co-SiW@GO-10, Co-SiW@GO-20, Co-SiW@GO-30 and Co-SiW@GO-40, were prepared with different contents of GO. The amorphous parts of Co-SiW were produced with the increased contents of GO during the preparation of the Co-SiW@GO system. The amorphous part of Co-SiW in Co-SiW@GO exposes abundant active sites, which makes lithium ions easily contact with them. Remarkably, the stability and electrical conductivity of Co-SiW@GO are markedly improved. The optimal Co-SiW@GO-30 features remarkable rate capability and satisfied lithium-ion storage capacity, which are comparable or even better than those known polyoxometalate-based anodes for LIBs. This amorphous engineering strategy affords a feasible route for the development of highly efficient alternative anode materials for LIBs.