In conventional tungsten oxide-based electrochromic batteries (ECBs), tungsten oxide acts as the cathode and Zn foil as the anode, but low redox potential leads to a limited discharge plateau, low areal capacitance, and power density, restricting practical applications. In this study, a novel WO₃||acid-modified graphite foil (WO₃||AGF) ECB was developed using AGF as the cathode, WO₃ as the anode, and a hybrid Zn²⁺/Al³⁺ electrolyte. The AGF offers advantages, such as high ion storage capacity, fast kinetics, and a high electrode potential, ensuring a high discharge voltage and capacity for the WO₃||AGF ECB. The prepared WO₃||AGF ECB not only exhibits excellent electrochromic performance but also demonstrates superior energy storage capabilities. At a charge/discharge current density of 0.5 mA·cm⁻², the WO₃||AGF ECB achieves a stable discharge capacity of 315.6 mAh·m⁻², which is 7.8 times higher than that of the traditional Zn||WO₃ ECB. Moreover, the rapid ion diffusion kinetics of the AGF ensure the cycling stability of the device at high voltages, maintaining 94.4% optical modulation after 8000 coloring/bleaching cycles. This work provides a novel approach by designing more compatible electrode material systems to achieve ECBs with high energy and power densities.

Sustainable energy conversion and storage technologies are a vital prerequisite for neutral future carbon. To this end, carbon materials with attractive features, such as tunable pore architecture, good electrical conductivity, outstanding physicochemical stability, abundant resource, and low cost, have used as promising electrode materials for energy conversion and storage. Defect engineering could modulate the structures of carbon materials, thereby affecting their electronic properties. The presence of defects on carbons may lead to asymmetric charge distribution, change in geometrical configuration, and distortion of the electronic structure that may result in unexpected electrochemical performances. In this review, recent advances in defects of carbons used for energy conversion and storage were examined in terms of types, regulation strategies, and fine characterization means of defects. The applications of such carbons in supercapacitors, rechargeable batteries, and electrocatalysis were also discussed. The perspectives toward the development of defect engineering carbons were proposed. In all, novel insights related to improvement in high-performance carbon materials for future energy conversion and storage applications were provided.