Li metal with ultra-high theoretical capacity is a promising anode for next-generation high-energy–density battery technologies. Nevertheless, the uncontrolled Li dendrite growth, continuous interfacial side reactions and irregular volume expansion bring about rapid capacity decay of Li metal anodes (LMAs). Herein, we design a bilayer host structure with an electronic conductivity gradient through a facile blade coating strategy to regulate Li deposition behavior. The electronic-insulative Si3N4 top layer prevents the apical growth of Li dendrites and promotes the penetration of electrolytes into the host so as to lower electrode polarization. The carbon black/LiNO3 mixed bottom layer creates mixed electronic-ionic conductive network to enhance the charge transfer kinetics of Li ions and lower Li nucleation barrier. Moreover, we first discover that the Si3N4 protective layer avoids the cell failure resulting from the dissolution of LiNO3 in ether electrolytes, enabling the Si3N4-C/LiNO3 electrode to operate smoothly for over 600 cycles, delivering an average Coulombic efficiency of up to 98.65 %. Furthermore, the Si3N4-C/LiNO3-composited LMAs paired with 10.5 mg cm−2 LiFePO4 cathodes achieve 200 stable cycles at a low N/P ratio of 1 under corrosive carbonate ester electrolytes, with an anode capacity utilization ratio as high as 50 %. This is the first report on the LiNO3-modified host materials that exhibit superior electrochemical properties in ether electrolytes, shedding a new light on the structural design of LMAs to enable high-energy–density Li metal batteries.

Link：A bilayer host electrode strategy for lithium metal anode to enable superior cycling performance and capacity utilization - ScienceDirect