High-Performance Li-Metal-Free Sulfur Battery Employing a Lithiated Anatase TiO2 Anode and a Freestanding Li2S-Carbon Aerogel Cathode

Lithium-sulfur (Li-S) batteries have emerged as promising alternatives to Li-ion batteries. The commercial feasibility of Li-S batteries is still in question due to the usage of a highly reactive Li-metal anode and complex electrochemistry of the sulfur cathode. We demonstrate here a sulfur battery that is free of both the lithium-metal anode and sulfurelement (S-8) cathode. Instead of a carbonaceous material, a lithiated anatase titanium dioxide (TiO2) nanoparticle is chosen here as the anode. A freestanding pellet of lithium sulfide and carbon aerogel (Li2S/CA) is used as the cathode in the Li-metal-free sulfur battery. Activation of Li2S and its conversion to S-8 are confirmed by in operando Raman spectroscopy. UV-vis spectroscopy clearly shows high retention of intermediate polysulfides inside the Li2S/CA pellet. The cell with the freestanding Li2S/CA cathode (Li2S-loading approximate to 10 mg cm(-2)) and the TiO2 anode shows remarkable electrochemical performance at current rates varying from 0.1C (1st cycle: 565 mAh g(-1); 200th cycle: 370 mAh g(-1)) to 1C (approximate to 200 mAh g(-1)). The Li2S/CA also performed remarkably well with the Li-metal anode in the current rate range from 0.1C (1st cycle: 955 mAh g(-1); 200th cycle: 855 mAh g(-1)) to 2C (average specific capacity@1C approximate to 380 mAh g(-1)).