Tuning the Interfacial Electronic Conductivity by Artificial Electron Tunneling Barriers for Practical Lithium Metal...

The native solid electrolyte interphase (SEI) in lithium metal batteries (LMBs) cannot effectively protect Li metal due to its poor ability to suppress electron tunneling, which may account for the increase of the SEI and even dead Li. It is desirable to introduce artificial electron tunneling barriers (AETBs) with ultrahigh insulativity and chemical stability to maintain a sufficiently low electronic conductivity of the SEI. Herein, a nanodiamond particle (ND)-embedded SEI is constructed by a self-transfer process. The ND serving as the AETB reduces the risk of electron penetration through the SEI, readjusts the electric field at the interface, and eliminates the tip effect. As a result, a dendrite-free morphology and dense massive microstructure of Li deposition are realized even with high areal capacity. Notably, full cells using ultrathin Li anodes (45 μm) and LiNi_0.8Co_0.1Mn_0.1O₂ cathodes (4.3 mA h cm^-2) can cycle stably over 110 cycles, demonstrating that the AETB-embedded SEI significantly alleviates the anode pulverization and safety concerns in practical LMBs.