We performed NeXT experiments at the BT-2 imaging beamline at the National Institute of Table . Neutron and X-ray linear attenuation coefficients at 0.18 nm neutron wavelength and 26.9 keV X-ray energy respectively for the battery materials of interest. We have used the peak Xray energy (see Figure (B) for spectrum) for calculating 𝝁 𝐗_𝐭𝐨𝐭 , which is a valid approximation given the materials thickness in the anodes. We computed the X-ray coefficients from tabulated material cross sections. For graphite, database-derived values for both neutron and X-rays took its composition and porosity into consideration. For LiOH and copper, we assumed fully dense materials for the calculations. Detailed calculations are given in Supporting Information#2.