The smaller cations have colorations efficiencies between 40-50 cm 2 /C, while the larger cations have coloration efficiencies between 12-15 cm 2 /C (Table ). The higher coloration efficiency in the visible range for Li + and Na + is consistent with our hypothesis that polaronic electrochromism leads to enhanced visible light modulation due to the intercalation of these smaller cations. Prior literature has suggested that even though Li + has a smaller ionic radius than the spacing of the trigonal channels in the crystal structure, it is still not able to diffuse through these smaller channels. Although, prior work done by Heo et al.