Well-aligned, ordered, nanocolumnar, Cu–Si thin film as anode material for lithium-ion batteries

Nanocolumnar composite Cu–Si films were produced as anodes using an oblique angle electron beam co-evaporation method. Two evaporation durations were used to yield different film thicknesses: thin (400 ± 100 nm). The structural and morphological properties of these Cu–Si films were characterized using X-ray diffraction and scanning electron microcopy. Galvanostatic half-cell electrochemical measurements were conducted over a voltage range of 50 mV–2.5 V using Li as a counter electrode and the Cu–Si films as anodes. The results demonstrated that the thin film has homogeneously distributed nanocolumns and yielded good cyclability upto 100 cycles with high capacity retention; by contrast, the thick film has an inhomogeneous porous structure and exhibited poor cyclability. The reason for the better electrochemical performance of the thin film was determined by X-ray photoelectron spectroscopy (XPS) at different states of charge. Moreover, in-situ electrodilatometric analysis during the galvanostatic test of the thin films measured the ongoing volumetric changes upon cycling. •Well-aligned, ordered nanocolumnar CuSi thin film is formed via OAD method.•In-situ dilatometry is done to measure the expansion of the CuSi thin film anode.•Long evaporation duration leads broadening of the nanocolumns.•Homogeneous distributions of porosity and Cu enhance the cyclability of the Si.