Fig. 3

Cycling performances of amorphous Si anode films. The films show areal capacities of ~2 mAh cm⁻² at a current density of 0.1 mA cm⁻². a, b Galvanostatic charging/discharging potential profiles of a non-porous and b porous Si films during the first five cycles: the black, red, green, blue and cyan curves indicate the profiles in the 1st, 2nd, 3rd, 4th and 5th cycles, respectively. c Charging/discharging capacities plotted against the cycle number. The filled and empty circles indicate the charging and discharging capacities, respectively; the black and red circles represent the results for non-porous and porous Si films, respectively. d, e Differential capacity curves for d non-porous and e porous Si films: the red, orange, green, light blue and purple curves indicate those in the 20th, 40th, 60th, 80th and 100th cycles, respectively. The curves were calculated from the corresponding galvanostatic charging/discharging potential profiles of the films. The areal mass loadings of the as-prepared non-porous and porous films were 0.70 and 0.74 mg cm⁻², respectively, and the thicknesses were 3.00 and 4.73 µm, respectively