Electrodeposition and Characterization of Manganese Dioxide Thin Films on Silicon Pillar Arrays for 3D Thin-Film Lithium-Ion Batteries Y. Zargouni a ,b, c, d , S. Deheryan b, d , A. Radisic b , D. J. Cott b , S. Rochan b,d , K. Alouani c , C. Huyghebaert b , P. M. Vereecken b, d a KACST-Intel Consortium Center of Excellence in Nano-Manufacturing and Applications (CENA), Riyadh 11442, Saudi Arabia b IMEC, Leuven 3001, Belgium c LR 99ES15-Unité de synthèse organique et de chimie de coordination, Faculté des sciences de Tunis, Université de Tunis EL Manar, 2092, Tunis, Tunisie d Centre for Surface Chemistry and Catalysis, Leuven University, Leuven 3001, Belgium In this paper, we evaluate PECVD carbon coating for TiN/Si substrate as a technologically relevant current collector for 3D thin film Lithium ion battery applications. Carbon coated TiN/silicon pillars (with aspect ratio of 30) served as substrate for electrolytic manganese dioxide (EMD) deposition from aqueous bath to be tested as positive electrode for Lithium ion batteries. Reversible insertion and extraction of Li + is observed showing an improved cycle performance for carbon coated TiN substrates compared to Pt coated TiN substrates. The average lithium storage capacity for planar EMD films is about 50Ah/cm 2 (at 10mV/s comparable with charging rate of 20 C). Based on a surface area gain of 28 for the 3D pillar structures, a capacity of 0.2mAh/cm 2 is expected for conformal coated 200 nm film at these high rates. Introduction With the increasing power requirements for electronic devices and emerging technologies (e.g., wireless transmission) the need to improve power supply sources is also increasing (1). Li-ion microbatteries provide the highest battery capacity and they are used to power a wide range of small and smart electronic devices with several applications. However, to increase the energy density of these microbatteries further and to ensure a high power delivery, three-dimensional (3D) designs are essential (5). 2D thin film battery structures result in a compromise between energy density and power density because of the limited surface area (2). By coating the thin film stack on a nanostructured 3D structure, the loss in electrode active material is compensated leading to the increase of the battery capacity. 3D structured electrodes are designed to provide shorter ion diffusion paths and improve electron harvesting pathways (3, 4) so that the recharging of device is fast and the battery power is increased. Incorporated in a foil technology, 3D thin film batteries can ensure an ultrafast charging of handheld electronic devices. 10.1149/06109.0029ecst ©The Electrochemical Society ECS Transactions, 61 (9) 29-41 (2014) 29 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 197.15.38.73 Downloaded on 2014-10-16 to IP