Effects of Cu substrate morphology and phase control on electrochemical performance of Sn–Ni alloys for Li-ion battery

The influence of substrate morphology and ageing on the charge–discharge performance of a Sn–Ni alloy anode electrodeposited on a Cu substrate are examined. The Sn–Ni alloy (Sn 82 at.%–Ni 18 at.% anode) shows a high capacity of around 480 mAh g−1 up to 12 cycles, but its capacity rapidly fades with cycling. The initial capacity and the cyclic properties of the alloy electrode are significantly improved when the surface morphology of the Cu substrate is changed from smooth-type to nodule-type. Optimized ageing treatment leads to further enhancement in the charge–discharge performance of the anode. The increase in the capacity and better cyclic properties are attributed to stronger adhesion between the Si–Ni anode and the Cu substrate. This is induced by inter-locking of the nodule-type Cu substrate and a buffering effect of Cu–Sn intermetallic compounds formed during ageing.