Dynamic charge modulate lithium uniform plating functional composite anode for dendrite-free lithium metal batteries

Abstract

Lithium metal is considered as the ‘sharp blade’ to break through the limitation on energy density of lithium batteries. However, uneven plating of lithium metal during charge/discharge process causes serious safety hazards. Here, a carbon-based 3D skeleton (CC@Co-NCNTs) with Co nanocrystals anchored N-containing carbon nanotubes (Co-NCNTs) was constructed to induce the uniform lithium plating towards dendrite-free lithium metal batteries. The Co-NCNTs in the skeleton exhibit enhanced lithophilicity, supplying abundant nucleation sites. Moreover, the ingenious hierarchical structure reconstructs the current density distribution, promoting the uniform lithium plating. Particularly, the electrons from the Co nanocrystals are transferred to the surface of Co-NCNTs, which offers a dynamic charge distribution on the surface of the skeleton along with the plating of lithium ions during the charge-discharge process, thus modulating uniform lithium plating on the Co-NCNTs skeleton. The above-mentioned mechanism is further verified by first-principle calculations and multi-physical field simulation. Thus, the CC@Co-NCNTs@Li symmetric cell presents a long-term cyclic stability (over 1300 h) at a high current density of 40 mA cm−2. The CC@Co-NCNTs@Li/LiFePO4 cell still delivers a discharge capacity of 135 mAh g−1 at 1 C after 500 cycles. This work provides new insights to the study of functional skeletons for dendrite-free lithium batteries.