High Electrochemical Performances of Tin Sulfide Nanosheet Electrodes Directly Grown on Current Collectors

Abstract

Self-supported low-dimensional nanostructuring of electrode materials on current collectors is one of attractive strategies for advanced Li ion battery by providing shorter path length for both electronic and Li ionic transport, higher electrode/electrolyte contact area, better accommodation of the strain of volume change during cycling, and especially good electrical contact between each array and the current collector. Herein, we fabricated two-dimensional (2-D) nanosheet arrays of high-capacity tin sulfide (SnS) directly grown on metallic current collector via the one-step pulsed laser ablation method. It was found that nanosheets have tens of nanometers thickness and hundreds of nanometers width. The preferential formation of sheet-like morphologies originates from weak Van der Waals force between two layers along the <010> direction in orthorhombic SnS structure. Electrochemical measurements such as cyclic voltammetry and galvanostatic cycling were performed to evaluate lithium reactivity of nanosheet electrodes. Indeed, SnS nanosheet electrodes show high reversible capacity and superior rate capability compared to its powder counterpart with lamellar structure. The origin of improved electrochemical performance and reaction mechanism upon cycling in SnS nanosheet electrodes are also investigated using high resolution transmission electron microscopy.