Binder-Free Metal Sulfide Composite Nanosheet Array Electrodes for Li-Ion Batteries

In this work, metal sulfide composite nanosheet arrays are directly grown on Ni foam substrates using chemical bath deposition to construct binder-free electrodes for Li-ion batteries. Structural characterizations indicate that the nanosheets are composed of nickel cobalt sulfide and nickel sulfide nanocrystals with sizes of 2–5 nm embedded in an amorphous matrix. Superior reversible capacity, cycling stability, and rate performance are acquired from the binder-free metal sulfide composite nanosheet electrode compared to the binder-free granular metal sulfide composite film electrode, which is attributed to the unique morphology and structure of the nanosheet array. At a current density of 200 mAg –1, 10% capacity loss is acquired from the binder-free metal sulfide composite nanosheet electrode after 100 cycles. The nanosheet electrode also exhibits a promising rate performance that the reversible capacities of 1860, 1610, 1350, 1170, and 1050 mAhg –1 are measured at current densities of 200, 500, 1000, 2000, and 3000 mAg –1, respectively.