Novel Stimuli‐Responsive Turbostratic Oxides/Hydroxides for Material‐Driven Robots

Abstract

Herein, a novel class of high‐performing actuating oxides/hydroxides with turbostratic crystal structures is reviewed. These materials, including nickel hydroxide/oxyhydroxide, cobalt oxides/hydroxides, nickel‐doped cobalt oxides/hydroxides, and manganese oxides, exhibit a volume‐changing redox reaction, rendering them an electrochemical actuation behavior. Also, due to their turbostratic crystal structures, they typically exhibit light‐driven actuation due to water deintercalation from the crystal structure induced by light. Compared with other actuating materials, these oxides/hydroxides actuate with high stress and strain at fast rates, under very low stimuli requirements. Furthermore, they are easily printable on different substrates, thus allowing flexible robots with demodularized muscle‐skeletal designs to be made.