Single-atom cobalt modified amorphous WO3·xH2O for enhanced electrochromic performance

Amorphous tungsten trioxide electrochromic materials exhibit faster ion transport kinetics than crystalline structures. This makes them a highly promising material for smart windows, electrochromic batteries, and other cutting-edge fields. Nevertheless, the complex preparation process (high temperature and pressure), low spectral modulation ability, and poor durability severely limit their practical applications. Herein, based on the guidance of DFT calculations, amorphous Co-WO 3 ·xH 2 O film was prepared by electrodeposition at room temperature and normal pressure. This synthesis employed a co-modification strategy involving single-atom Co doping and structural water, achieved by adjusting the components of precursor solution. Theoretical calculations and experimental results indicate that Co doping significantly improved the electronic conductivity of WO 3 and consequently elevated its electrochemical performance. The Co-WO 3 ·xH 2 O film exhibited rapid response (1.3 s of bleaching time at 633 nm), durable cycling stability (merely 0.3 % capacity loss after 1000 cycles), and outstanding thermal management performance (9.1 °C lower than Low-e glass). Furthermore, Energyplus simulation indicates that our device has outstanding energy-saving capabilities in China and in most climate zones around the world. This simple strategy does not require complex high-temperature and high-pressure conditions, nor does it require a sealed environment. The excellent dual-band electrochromic smart window has great potential in reducing energy consumption in the interiors of buildings.