A Cost- and Energy Density-Competitive Lithium-Sulfur Battery

Attaining jointly high energy density at low cost is extremely challenging for lithium-sulfur (Li-S) batteries to compete with commercially available Li ion batteries (LIB). Here we report a class of bio-derived dense self-supporting cathode with ultralow porosity of 0.4 via self-densification effect during thermal drying without mechanical compression to realize a low-cost Li-S cell with high gravimetric/volumetric energy densities. Benefiting from the great preponderances of biochar, jointly high gravimetric/volumetric energy densities of 422 Wh kg−1/446 Wh L − 1 are achieved under conditions of high mass loading (6.5 mg cm−2) and extremely lean electrolyte (2.5 μL mg−1), the corresponding costs based on sub-Ah level pouch cell are estimated to be as low as $60/kWh-$90/kWh for the initial 20 cycles via a materials-to-system analysis, which is visibly less than that in the typical commercial LIB ($100/kWh). The current study presents meaningful opportunity to develop commercially viable Li-S batteries that are competitive on a specific energy/cost basis with current state-of-the-art LIB.