High Power and High Capacity 3D-Structured TiO₂Electrodes for Lithium-Ion Microbatteries

An on-chip compatible method to fabricate high energy density TiO 2 thin film electrodes on 3D-structured silicon substrates was demonstrated. 3D-structured electrodes are fabricated by combining reactive ion etching (RIE) with low pressure chemical vapor deposition (LPCVD), enabling accurate control of the aspect ratio of substrates and the subsequent deposition of TiO 2 thin film electrodes onto these structured substrates. The prepared 3D-TiO 2 electrodes exhibit a current-dependent increase in storage capacity of a factor up to 16 as compared to conventional planar electrodes. In addition, these 3D electrodes also reveal excellent power and cycling performance. This work demonstrates that LPCVD is capable of depositing homogeneous film electrodes on highly structured substrates and the prepared 3D-electrodes also shows significant improve in storage capacity and power density.