Fast capture and stabilization of Li‐ions via physicochemical dual effects for an ultra‐stable self‐supporting Li metal anode

Abstract

Abstract Lithium (Li) metal is regarded as one of the most promising anode candidates for next‐generation batteries due to its extremely high specific capacity and low redox potential. However, its application is still hindered by the uncontrolled growth of dendritic Li and huge volume fluctuation during cycles. To address these issues, flexible and self‐supporting three‐dimensional (3D) interlaced N‐doped carbon nanofibers (NCNFs) coated with uniformly distributed 2D ultrathin NiCo2S4 nanosheets (denoted CNCS) were designed to eliminate the intrinsic hotspots for Li deposition. Physicochemical dual effects of CNCS arise from limited surface Li diffusivity with a higher Li affinity, leading to uniform Li nucleation and less random accumulation of Li, as confirmed by ab initio molecular dynamics simulations. Due to the unique structure, exchange current density is reduced significantly and metallic Li is further contained within the interspace between the NCNF and NiCo2S4 nanosheets, preventing the formation of dendritic Li. The symmetric cell with a Li/CNCS composite anode shows a long‐running lifespan for almost 1200 h, with an exceptionally low and stable overpotential under 1 mA cm−2/1 mAh cm−2. A full cell coupled with a LiFePO4 cathode at a low N/P ratio of 2.45 shows typical voltage profiles but more significantly enhanced performance than that of a LiFePO4 cathode coupled with a bare Li anode.

Keywords

• 3D scaffold design
• Li affinity
• Li diffusivity
• Li metal anode
• long lifespan