Conductivity gradient modulator induced highly reversible Li anodes in carbonate electrolytes for high-voltage lithium-metal batteries

Lithium metal has been considered as the ultimate anode for rechargeable batteries due to its lowest redox potential and ultra-high theoretical capacity. Nevertheless, uneven Li deposition, uncontrolled dendrite growth, and fragile solid electrolyte interphase (SEI) seriously impede the widespread application of lithium-metal batteries (LMBs), especially those cycled in carbonate electrolytes. Herein, a flexible LiNO3-modified conductivity gradient host (LNO-CGH), which comprises a dielectric top layer with excess decorated LiNO3 particles and carbon nanofiber layers with upward attenuation of electrical conductivity, is demonstrated to manipulate Li deposition behavior in carbonate electrolytes. The top layer can steadily release LiNO3 to form a robust nitride-rich SEI while the conductivity gradient structure endows Li deposited in a dendrite-free manner by shifting the preferential deposition spots from the anode/separator interface to the anode bottom, which is confirmed through experiments and simulations. Benefiting from the elaborate and comhensive design, the stability of LNO -CGH electrodes was significantly improved. The full cell with limited LNO-CGH@Li anodes and high mass-loading LiNi0.8Co0.1Mn0.1O2 cathodes (N/P ratio of 2.3) can work stably for over 60 cycles with 72.9% capacity retention. As a proof-of-concept, flexible quasi-solid electrolyte can also be assembled with the as-obtained anode enables flexible LMB with excellent electrochemcial performance.