Twisted nanocolumns for LIBs via phi-sweep method in ion assisted e–beam deposition

In this work, twisted nanostructured silicon-copper (with 19%at. copper) thin film is fabricated by glancing angle deposition phi-sweep process of ion beam assisted electron beam evaporation method. The thin film delivers 977 mAh g−1 after 100 cycles, when cycled with 100 mA g−1 rate and performs 280 mAh g−1 at 2.5 A g−1 rate. The morphological and the compositional particularities of the electrode might govern this noticeable cycle performance: Gaps among the nanostructures accommodate large volume changes and provide easy access to lithium ions for reacting with silicon to deliver high capacity. Plus, the direct connection of nanostructures to the current collector displays short lithium travelling distance promoting lithiation kinetic. Moreover, small intermetallics creating electronic conductive pathways enhance the reversibility. And finally, 5 min ion assisted deposition increases the adhesion of the film while avoiding possible delamination, hence quick failure of the electrode in the early stages of cycling. •Phi-sweep method was first used to fabricate a twisted nanocolumnar SiCu thin film.•Ion assistance is adapted to GLAD to increase the adhesion of the films.•Twisted nanocolumnar SiCu thin film delivers 977 mA h/g at the 100 t h cycle, at 100 mAg−1.•Twisted nanocolumnar SiCu thin film cycles even at 2.5 mAg−1.•Material selection and electrode design are successfully done.