Silicon anode materials for all-solid-state lithium-ion microbatteries

Driven by the fast development of autonomous devices, all-solid-state microbatteries attract intense attention recently. Silicon is an excellent anode candidate for Li-ion batteries due to its extremely high storage capacity. However, the volume expansion induces tremendous material deterioration, resulting in poor cycle life. In order to cope with this shortage, various strategies
have been proposed. Nanowires were found to be mechanically too fragile to be applied in allsolid-state battery stacks. Honeycomb structures have recently been proposed as they can sustain striking reversible deformations upon (de)lithiation. Finally, thin films turn out to be extremely stable. To further increase the energy density of these thin-film batteries, novel approaches have
been proposed. One of the new concepts is based on the etching of deep 3D-structures into a Si substrate, increasing the effective surface area significantly. In combination with advanced materials, new opportunities are obtained to increase the energy density further.