Facile synthesis of a Ni3S2@C composite using cation exchange resin as an efficient catalyst to improve the kinetic properties of MgH2

•Ni3S2@C composites were prepared using cheap cation exchange resins and Ni(CH3COO)2 4H2O.•The comprehensive hydrogen storage performance of MgH2was significantly improved by the addition of Ni3S2@C.•The hydrogenation apparent activation energy of MgH2-Ni3S2@C-4 was 39.6 kJ mol−1.•The multi-phase (Mg/Mg2Ni, Mg/MgS, and Mg/C) interface provided more active sites to improve the hydrogen storage performance of MgH2.