Facile synthesis of Co9S8 nanosheets for lithium ion batteries with enhanced rate capability and cycling stability

Abstract

Two-dimensional Co₉S₈ nanosheets with a thickness of ∼10 nm and lateral size of several hundred nanometers are facilely synthesized through a polyvinyl alcohol (PVA)-assisted precipitation process in an aqueous solution. The process has low energy consumption and is easy to scale-up. Compared to the Co₉S₈ nanoparticles with a diameter of 40 nm prepared through the same process without PVA, the Co₉S₈ nanosheets, employed as anode materials in lithium-ion batteries, exhibited enhanced rate capability and cycling stability due to their unique two-dimensional nanostructures. When discharging/charging at 1.0 A g⁻¹, the Co₉S₈ nanosheets can deliver a reversible capacity as high as 746.8 mA h g⁻¹ after 300 cycles, which is much higher than that of Co₉S₈ nanoparticles (63.6 mA h g⁻¹), making the Co₉S₈ nanosheets promising candidates for anode materials in high-energy and high-power lithium ion batteries.