A dendrite-free Li plating host towards high utilization of Li metal anode in Li-O₂ battery

The intense interest of Li-O₂ battery stems from its ultrahigh theoretical energy density, but its application is still hindered by the issues of Li anode. Herein, RuO₂-CNTs composite, a conventional O₂ cathode catalyst in Li-O₂ battery, is first utilized as an anode host for dendrite-free Li plating/stripping with high Coulombic efficiency. It is demonstrated that such excellent plating/stripping performance arises from the lithiophilicity characteristic of Ru nanoparticles (that is derived from the in-situ electrochemical conversion from RuO₂ to Ru/Li₂O) and buffer space provided by CNTs. Furthermore, the RuO₂-CNTs electrode pre-deposited with limited Li (RuO₂-CNTs@Li anode) is coupled with a RuO₂-CNTs catalytic cathode to form a Li-O₂ full cell, which displays an extended cycle life with dramatically improved energy density. The achieved cell shows a high stability of 200 cycles with RuO₂-CNTs@Li anode (1 mg Li) that sheds light on the efficient utilization of Li anode in Li-O₂ batteries.