An efficient Li₂S-based lithium-ion sulfur battery realized by a bifunctional electrolyte additive

Previous investigations have shown that high-energy lithium-ion sulfur batteries could be directly assembled with lithium sulfide (Li₂S) cathode and a non-lithium anode. However, the existing lithium-ion sulfur battery suffers from the multistep sophisticated preparation process, high activation potential and also polysulfides corrosion to the anode. In this work, we propose and prepare a facile and feasible Li₂S-based lithium-ion sulfur battery system, which is enabled by a bifunctional electrolyte additive. At first, Li₂S particles were loaded on the low-cost carbonized commercial wipes by a solution-based infiltration method. Interestingly, for the first time, it is found that the well-designed indium triiodide (InI₃) electrolyte additive not only performed as a cathodic redox mediator, reducing the activation potential of Li₂S cathode, but also resulted in a passivation layer, preventing the anode from corrosion due to the shuttle effect. The obtained SnO₂/Li₂S full cell exhibits a stable electrochemical performance (983, 878, 746 and 675 mA h/g at 0.2, 0.4, 0.8, and 1.5 C, 647 mA h/g after 200 cycles at 0.5 C). Moreover, the manageable amount of lithium ions and the voltage cooperation between the cathode and anode in the full cell rendered the battery with a strong recovery ability against the abusive conditions test, such as over-charge, over-discharge and short-circuit, showing a great potential for practical use.