In a significant advancement for energy storage technologies, researchers have developed a novel flexible carbon nanotube@porous carbon (CNT@PC) sponge cathode material, enhancing the charging performance and efficiency of zinc ion hybrid capacitors (ZIHCs).
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Traditional ZIHCs, while promising in terms of energy and power density, have been hampered by the limited rate capability of carbon-based cathodes. The mismatch between the micropores in the carbon matrix and the large hydrated Zn ions has been a significant barrier, impeding the rapid charging capabilities essential for modern applications. This limitation has been a focal point of research, driving the quest for a material that can overcome these constraints.
In a new breakthrough, researchers have engineered a flexible CNT@PC sponge characterized by larger mesopores averaging 14.3 nm in size. This structure facilitates a high specific capacity of 175.3 mAh/g at a low current density (0.1 A/g) and maintains a high rate capability of 93.1 mAh/g even at a substantial current density (50 A/g). The large mesopores in the CNT@PC sponge play a crucial role, enabling rapid ion transport, significantly lowering internal resistance (IR drop) and reducing ion diffusion resistance.
The CNT@PC sponge showcases a high ion diffusion coefficient and substantial surface capacitive contributions, key factors for efficient energy storage and rapid charge-discharge cycles. Additionally, the material's flexibility positions it as an ideal candidate for applications where mechanical stress and flexibility are considerations, such as in wearable electronics and bendable devices.
The research delves deep into the influence of pore size on the rate capability of porous carbon (PC) cathodes. By adopting a meticulous approach to pore structure engineering, the team has created a cathode material that significantly enhances the fast-charging performance of ZIHCs. The study illustrates that large mesopores not only support rapid ion transport but also minimize energy loss, a critical aspect in high-rate applications.
The practical implications of this development are substantial. In electric vehicles, where rapid charging is a crucial factor, the CNT@PC sponge-based ZIHCs could lead to significant improvements in charging time and battery life. In the realm of portable electronics, this technology promises to deliver more reliable and longer-lasting power sources capable of withstanding various mechanical stresses.
This advancement opens new avenues for the development of high-performance energy storage systems. The insights gained from this research could inform future innovations in the design of porous carbon-based cathodes, extending the potential applications of ZIHCs to a broader spectrum of energy storage technologies.
Source
Boyu Yang a b et al. (2023) Flexible cnt@porous carbon sponge cathode with large mesopores for high-rate zinc-ion hybrid capacitors, Carbon. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0008622323009405 (Accessed: 30 November 2023).