A fast and stable Li metal anode incorporating an Mo6S8 artificial interphase with super Li-ion conductivity†
The poor interfacial stability of Li metal leads to formation of unstable solid-electrolyte interphases (SEIs) and severely limits its practical applications. Protecting Li metal with an artificial SEI that has balanced stability, conductivity and mechanical strength is critical. Here we demonstrate a design strategy for stabilizing Li using Mo6S8/carbon artificial SEI films. These films are directly coated on Li foil and the Mo6S8 particles provide ordered conduction channels for fast but regulated Li-ion flux, and provide hybrid anodes that have nearly four times higher exchange current densities. They also have seamless contact with Li metal and protect it from parasitic reactions, and hence significantly improve its stability. Consequently, Li metal batteries in which the hybrid anodes were paired with LiNi0.8Mn0.1Co0.1O2 cathodes (3.0 mA h per cell) exhibited significantly improved cycling stability (63% vs. 25% retention) and a stabilized Li interphase compared with pristine Li anodes.