Boosting the energy density of 3D dual-manganese oxides-based li-ion supercabattery by controlled mass ratio and charge injection

Supercabatteries, combining the energy of secondary batteries with the power of supercapacitors, have attracted significant attention in the energy storage research and market field. Herein, we continued our previous 3D electrode works and fabricated supercabatteries with the prelithiated ACNTs@MnOx positive and C/MnOy/ACNTs negative electrodes, which can offer ultrahigh discharge capacities and remarkable improved capabilities and stabilities. The theoretical specific capacities of the supercabatteries were calculated and predicted as function of the P/N mass ratios and initial potentials for the two electrodes, based on the half-cell results. The experimental specific capacities of the supercabatteries with different P/N mass ratios and charge injection pretreatments matched well with the prediction line. The supercabattery with a P/N mass ratio of 1.6 and optimized EPW delivered the maximum specific discharge capacity of 217 mAh g−1 and energy density of 208.6 Wh kg−1 based on the active materials. The supercabattery remained at 105.8 Wh kg−1 with a ultrahigh power density of 3000 W kg−1 and maintained 80% of the initial capacity after 1000 cycles.