Electrochemical performance of laser micro-structured nickel oxyhydroxide cathodes

This study describes the preparation and analysis of laser micro-structured nickel metal electrodes for application as a cathode material in micro-batteries based on the nickel oxyhydroxide chemistry. Using ultra-short pulse length lasers (picoseconds to femtoseconds); surface micro-structures in the form of ripples are rapidly generated at the surface of nickel metal cathodes. These ripple micro-structures, with a periodic spacing approximately equal to the wavelength of laser radiation used, are more commonly referred to as laser-induced periodic plasmonic structures (LIPPS). The electrochemical activity of the LIPPS nickel metal cathodes is investigated in aqueous KOH using cyclic voltammetry. Across a wide range of scan rates, the results of the voltammetry show that the formation of LIPPS yields a considerable enhancement in the electrochemical activity of the nickel surface. The observed enhancement is attributed to both the greater surface area of the rippled surface relative to a planar nickel surface and a thicker Ni sub(x), layer generated by the laser process.