Laser-induced breakdown spectroscopy to obtain quantitative three-dimensional hydrogen mapping in a nickel-metal-hydride battery cathode for interpreting its reaction distribution.

We present a method for obtaining a three-dimensional quantitative hydrogen distribution in a Ni-MH battery cathode using laser-induced breakdown spectroscopy (LIBS) and demonstrate that the reaction distribution in the cathode can be interpreted based on a state-of-charge (SOC) distribution converted from the hydrogen distribution. In this method, we measured the hydrogen emission-line intensities at 656.28 nm for a model cathode cycled five times at 2.3 mA cm