Cu2ZnSnS4/graphene nanocomposites for ultrafast, long life all-solid-state lithium batteries using lithium metal anode

A graphene-based nanocomposite Cu 2 ZnSnS 4 /graphene (CZTS/graphene) is employed as a promising active material for all-solid-state lithium batteries for the first time. Meantime, lithium metal is used as an anode in order to maximize the energy density of the batteries with the sulfide electrolytes. The solid electrolyte bilayer, i.e. Li 10 GeP 2 S 12 and 70% Li 2 S–29% P 2 S 5 –1% P 2 O 5 , is designed, where 70% Li 2 S–29% P 2 S 5 –1% P 2 O 5 is used as the interface with lithium metal for the purpose of avoiding the reduction reaction with Li 10 GeP 2 S 12 . CZTS/graphene nanocomposites, with the CZTS nanoparticles uniformly anchored on the graphene nanosheets , are prepared by a simple hydrothermal reaction . The unique structure endows significantly reduced lithium ion diffusion lengths in CZTS nanoparticles as well as intimate contact between CZTS nanoparticles and sulfide electrolytes, leading to favorable lithium ionic and electronic conduction pathways. The results reveal that the CZTS/graphene-21 in all-solid-state lithium batteries shows the discharge capacity of 645.4   mA   h   g −1 after 50 cycles at 50   mA   g −1 , corresponding to a very high energy density of 346.2   W   h   kg −1 . Even at high current densities of 100 and 1000   mA   g −1 , the CZTS/graphene-21 can still deliver the discharge specific capacities as high as 544.6 and 233.9   mA   h   g −1 after 100 and 300 cycles, respectively.