Transmission-mode XAS was conducted at beamline 2-2 at SSRL. To avoid pinholes and ensure a uniformly thick sample for analysis via XAS, a slurry of approximately 1:1 sample and polyvinylidene fluoride (PVDF) by mass in N-Methyl-2-pyrrolidone (NMP) was cast onto carbon-coated Al foil using a doctor blade set to a height of 100 µm. The slurry was dried at 65 °C overnight. A Si(220) ϕ=90°monochromator was used and was detuned to 50-60% of the maximum intensity to eliminate higher-order harmonics. The spectra of Ni and Mn reference foils were used to calibrate the photon energy by setting the first crossing of zero of the second derivative of the absorbance spectrum to be 8,333 and 6,539 eV, respectively.