Self-Assembled <i>o</i> -Carborane Clusters Enabling Ambient/Electrochemical Dual-Stable Interphases for Dendrite-Free and High-Rate Lithium Metal Batteries

The practical application of lithium (Li) metal batteries is severely hindered by the limited cycling lifespan and worrying safety concerns caused by unstable native solid electrolyte interphase (SEI) and uncontrollable Li dendrite growth. Herein, we report the spontaneous construction of a self-adsorbed <i>o</i>-carborane interfacial passivation layer on Li metal anodes via the electrostatic attraction between <i>o</i>-carborane molecules and Li metal. The electrochemically stable <i>o</i>-carborane clusters can fully participate in the formation of a hybrid SEI, which is endowed with high chemical inertness and structural stability, thus effectively preventing Li metal from electrolyte corrosion. Furthermore, the as-formed <i>o</i>-carborane-rich SEI can promote uniform distribution of Li⁺ flux and accelerate Li⁺ transfer, thereby avoiding dendritic Li formation and enhancing Li plating/stripping reversibility. Consequently, the Li||Li symmetric batteries assembled with <i>o</i>-carborane modified Li metal (<i>o</i>-carborane/Li) electrodes can cycle stably for over 800 h at 1.0 mA cm^-2 in carbonate-based electrolytes and 1000 h at 4.0 mA cm^-2 in ether-based electrolytes. The assembled <i>o</i>-carborane/Li||LiFePO₄ and <i>o</i>-carborane/Li||LiNi_0.8Co_0.1Mn_0.1O₂ batteries also achieve exceptional cycling reversibility, prolonged operation lifespan, and superior rate performance. This work offers a promising strategy to develop intriguing self-adsorbed passivation layers for the development of dendrite-free and high-rate Li metal batteries.