Grid-like Fe3O4 nanocrystals enhance the performances of glass-ceramic anodes for lithium-ion batteries

•High-performance Fe2O3-B2O3 glass-ceramic anode for Li-ion battery is developed.•The grid-like Fe3O4 nanocrystals form in 90Fe2O3–10B2O3 during melt quenching.•The fraction of ferrous ions and DC conductivity increase with Fe2O3 content.•The capacity and cycling stability are enhanced by the grid-like Fe3O4 nanocrystals.•The remarkable electrochemical performances are caused by the capacitive charge.