Crystalline diamond nanoparticles which are 3.6 nm in size adhering to thin-film silicon results in a hydrophilic silicon surface for uniform wetting by electrolytes and serves as a current spreader for the prevention of a local high-lithium-ion current density. The excellent physical integrity of an anode made of diamond on silicon and the long-life and high-capacity-retention cycling performance are thus achieved for lithium-ion batteries. A specific capacity of 1860 mAh/g(si) was retained after 200 cycles of discharge/charge at an areal current density of 0.2 mA/cm2. This is compared to 1626 mAh/g(si) for a thin-film-silicon anode without the additive of diamond nanoparticles.
