Single-atomic Zn-(C/N/O) lithiophilic sites induced stable lithium plating/stripping in anode-free lithium metal battery
For anode-free lithium metal battery, lithiophilic surface modification on the current collector can effectively reduce the lithium nucleation barrier, so as to regulate the electrodeposition of lithium. Here, atomically dispersed Zn-(C/N/O) lithiophilic sites in the amorphous carbon medium were introduced onto Cu by an in-situ induced ion coordination chemistry strategy to get the modified Zn@NC@RGO@Cu current collector. XAS combined with STEM-HAADF analysis proved the single atomic state of the zinc sites surrounded by C, N and O with a coordination number of ~3. According to the electrochemical tests and first principle calculations, the ultra-uniformly dispersed Zn-(C/N/O) sites at the atomic level can effectively improve the lithium affinity, reduce the energy barrier for lithium nucleation, homogenize the lithium nucleation, and enhance an inorganic lithium compounds rich solid electrolyte interphase layer. As a result, the nucleation overpotential of lithium on the modified current collector was reduced to 7.7 mV, which was 5.4 times lower than that on bare Cu. Uniform lithium nucleation and deposition enabled stable Li plating/stripping and elevated coulombic efficiency of 98.95% in Li||Cu cell after >850 cycles. Capacity retention of 89.7% was successfully achieved in the anode free lithium metal battery after 100 cycles.