The lithium/sodium-ion storage properties of transition metal oxides often undergo startling volume variation and poor electrical conductivity. Herein, N, P and S doped dual carbon-confined Fe3O4 nanospheres (Fe3O4@C@G) are prepared by the multi-heteroatom-doped dual carbon-confined strategy. The first carbon layer results from multi-heteroatom-containing polymer derived N, P and S doped carbon to form Fe3O4@doped carbon core-shell nanostructure. And the second carbon layer results from the further encapsulated reduced graphene oxide (rGO) to form Fe3O4@doped carbon@graphene 3D architecture (Fe3O4@C@G). As expected, the resulting Fe3O4@C@G can be served as the universal anode materials towards lithium/sodium-ion batteries (LIBs/SIBS). Interestingly, Fe3O4@C@G delivers higher reversible capacity of 919 mAh g(-1) at 0.1 A g(-1) for LIBs. As for SIBS, Fe3O4 @C@G also shows a high reversible capacity of 180 mAh g(-1) after 600 cycles at 0.1 A g(-1). Furthermore, the electrochemical reaction kinetics in LIBs/SIBS are investigated and Li+ full cells are also assembled to demonstrate its practical application. (C) 2020 Elsevier Inc. All rights reserved.