Fabrication of micro lithium-ion battery with 3D anode and 3D cathode by using polymer wall

New electrode architecture, in which a polymer wall exists in the gap between interdigitated current collectors on SiO2/Si substrate, was developed for micro lithium-ion batteries with high power and high capacity. The polymer wall with 30 mu m thickness was very helpful to construct 3D Li4Ti5O12 composite anode and 3D LiCoO2 composite cathode with an aspect ratio of similar to 0.5, resulting in a great improvement of cell capacity up to 270 mu A h cm(-2) from 4.8 mu A h cm(-2) of the cell previously prepared by sol-gel process for LiMn2O4 cathode and Li4Ti5O12 anode on a conventional non-wall electrode substrate. Furthermore, in the developed cell configuration with poly(methyl methacrylate) (PMMA) gel electrolyte, more than 60% of the discharge capacity at 2 C rate was retained at 20 C rate. (C) 2012 Elsevier B.V. All rights reserved.