nickel hydroxide electrochromism polyvinyl alcohol electrochromic device supercapacitor electrochemical deposition specific capacity Ni(OH)2 activation adhesion counter-electrode electrochemical activity electrodeposition layered (α+β) structure mesh electrode pigment silver template "smart" bi-functional pigment 3D printing KOH Ni-Al layered double hydroxide Tartrazine Zn-Al LDH Zn–Al layered double hydroxide acetate acetate group adsorption aging alkaline accumulator alkaline battery aluminum anode electrochromic material anodic behavior basic solution binary Ni-Co oxyhydroxide binder bleaching carbonate chloride melts coating thickness coloration current collector cyclic voltamperometry cycling degradation deposition duration discharge plateau electrochemical characteristics electrochemical nickel