Variable stoichiometry is a defining feature of the function of lithium amide-imide (LiNH2-Li2NH) as a highly-active ammonia decomposition catalyst and a solid state hydrogen store. While the existence and importance of the solid solution is known, quantifying the precise stoichiometry is challenging, hindering efforts to obtain a clear understanding of stoichiometry-dependent properties in the system. In this continuation proposal, we seek to build on our successful demonstration of the use of X-ray spectra from negative muon decay as a means of quantifying the stoichiometry of lithium amide-imide samples. We request 5 days on Port 4 at RIKEN to use a higher-resolution low-energy X-ray detector and an improved experimental setup to enable the precise and accurate determination of the stoichiometry of a wide range of lithium amide-imide samples.