Interconnected Ni Nanowire Scaffolds for Fast-Charging 3D Thin-Film Lithium-Ion Batteries

Abstract

The growing market of small consumer electronics, such as cell phones, smartwatches or electronic eyewear requires development of small power sources that allow for both satisfactory usage time and fast charging. Lithium-ion batteries (LIBs) are currently the systems of choice thanks to their high energy and power density. However, downscalling these batteries for small device applications still possess a big challenge. Due to electronically and ionically resistive nature of the active materials, mini-LIBs are currently made only in thin film technology, thus the total output energy and power density are still far too low for consumer device applications. Also, the manufacturing of thin film batteries requires sophisticated PVD/CVD deposition techniques. To overcome these issues, 3D architecturing of the current collector can be employed [1, 2]. This can provide a system where very thin active materials are stacked over enormously large surface area of a 3D current collector to yield a cell with both high power density (due to reduced materials thickness) and high energy density (thanks to large total volume of the active materials). Herein, we report reproducible fabrication of 3D-interconnected nickel nanowires (Fig. 1) prepared by electrodeposition of nickel into anodized aluminum oxide (AAO) template. The inter-branching of the wires provides rigidity of the structure, together with increase of the surface area of the current collector. The total surface area enhancement of the electrode was characterized by electrochemical passivation of the nickel nanowires and reached values up to 60x for 3 μm-long 3D nanoscaffolds. Additionally, we present results of electrodeposition of thin films of electrolytic manganese dioxide (EMD) on our 3D current collector and their activity as battery electrodes. This shows the potential of the 3D Ni-meshes for cheap fabrication of high power density electrodes for thin-film lithium-ion batteries. J. F. M. Oudenhoven, L. Bagetto, P. H. L. Notten, Adv. Energy Mater., 2011, 1, p. 10-33.J.Vanpaemel, A. M. Abd-Elnaiem, S. De Gendt, P. Vereecken, J. Phys. Chem. C, 2015, 119 (4), pp 2105-2112 Figure 1