AbstractThe lithium storage capacity of an iron oxide‐based anode of porous carbon–Fe3O4 (i.e., PC–Fe3O4) was investigated by varying the initial current and mass density of the electrode to achieve a good utilization coefficient of the oxide. It was confirmed that these factors largely affected the capacity of PC–Fe3O4 and a certain mass density of the electrode was key to achieve a high area capacity (μAh cm−2). Moreover, the chemical and electrochemical lithiation of PC–Fe3O4 were related to the lithiation time and pressure and both were both systemically studied. After optimization, a new battery of PC–Fe3O4/Li[Ni0.59Co0.16Mn0.25]O2 with a high area capacity of 748 μAh cm−2 (≈150 mAh g−1) and superior energy density of 483 Wh kg−1 (work voltage≈3.2 V) was developed. The battery showed reversible work ability in the rate window of 50–800 mA g−1, and also it could be charged/discharged for well over 1000 cycles with a capacity retention of 63.8 % under the high current value of 0.505 mA (current density, 50 mA g−1).