Plasma Enhanced Lithium Coupled with Cobalt Fibers Arrays for Advanced Energy Storage

Abstract Construction of high efficiency and stable Li metal anodes is extremely vital to the breakthrough of Li metal batteries. In this study, for the first time, groundbreaking in situ plasma interphase engineering is reported to construct high‐quality lithium halides‐dominated solid electrolyte interphase layer on Li metal to stabilize & protect the anode. Typically, SF 6 plasma‐induced sulfured and fluorinated interphase (SFI) is composed of LiF and Li 2 S, interwoven with each other to form a consecutive solid electrolyte interphase. Simultaneously, brand‐new vertical Co fibers (diameter: ≈5 µm) scaffold is designed via a facile magnetic‐field‐assisted hydrothermal method to collaborate with plasma‐enhanced Li metal anodes (SFI@Li/Co). The Co fibers scaffold accommodates active Li with mechanical integrity and decreases local current density with good lithiophilicity and low geometric tortuosity, supported by DFT calculations and COMSOL Multiphysics simulation. Consequently, the assembled symmetric cells with SFI@Li/Co anodes exhibit superior stability over 525 h with a small voltage hysteresis (125 mV at 5 mA cm −2 ) and improved Coulombic efficiency (99.7%), much better than the counterparts. Enhanced electrochemical performance is also demonstrated in full cells with commercial cathodes and SFI@Li/Co anode. The research offers a new route to develop advanced alkali metal anodes for energy storage.