• Energy Research

Zinc (Zn)‐based aqueous battery‐supercapacitor hybrid (BSH) devices are considered promising energy storage devices benefiting from their high energy and power densities, low‐cost, safety, and environmental benignity. However, challenges remain in the development of efficient BSH electrodes due to poor reversibility in battery electrodes and lack of efficient supercapacitor electrodes to solve the problems of low power and energy densities. Herein, the loading of iodine (I2) in the nanopores of 3D graphene‐like carbon (3DGC) for the fabrication of BSH electrodes and their device application with Zn are reported. The uniform micropores of 3DGC serve as nanocages to stabilize I2, the high surface area of 3DGC maximizes the dispersion, and the high conductivity of 3DGC provides a path for fast electron transfer. The resultant I2‐loaded 3DGC (I2/3DGC) is applied to evaluate Zn‐based battery and BSH performance. The I2/3DGC‐based electrode exhibits excellent performance with ultrahigh energy and power densities resulting from the high reversibility of I2 and supercapacitance of 3DGC. The device exhibits high cyclic stability in both battery and supercapacitor modes due to the confinement of I2 in the micropores. It is demonstrated that this combination of 3DGC with I2 provides an easy way to fabricate durable and economical BSH electrodes.

Abstract A major component of solar thermal systems is the solar absorber, which converts light into heat. We report on achieving high absorptance, excellent adhesion, and high thermal stability of carbon nanotube-based black coatings by applying a layer of Boehmite (AlOOH) on top of the carbon nanotube (CNT) film by solution-processed spray deposition. The CNT layer made-up by spraying, functions as an absorbing layer and the AlOOH serves as an anti-reflecting and protecting film. The anti-reflecting property of AlOOH layer effectively increases the absorptance of CNT coating by decreasing the reflectance. The effect of the thickness of AlOOH layer on the absorptance, adhesion, and thermal stability of the resulting CNT/AlOOH coating was investigated. The CNT/AlOOH coating with optimized thickness of AlOOH layer shows very high absorptance ( α ) of 0.975. The adhesion of the coating is in the range of 95–100% with significant increase of thermal stability. This new approach is expected to open new possibilities for fabricating low-cost, highly efficient and thermally stable solar-thermal devices which are based on simple coating processes.

AbstractWe report the fabrication of a new selective “inverse tandem” absorbing coating based on carbon nanotube (CNT)/indium‐tin oxide (ITO) on aluminium (Al) for mid‐temperature solar–thermal application. The CNT layer is formed by spraying and functions as an excellent solar absorber whereas the ITO layer produced on top of the CNTs by sputtering serves as an IR reflector. The effect of the thickness of the ITO on the spectral selectivity of the absorbing coating was investigated. Controlling the thickness of ITO allowed the spectral selectivity of the coating to be tuned. The CNT/ITO solar coatings with optimized thickness of ITO showed excellent spectral selectivity values of absorptance (α) of 0.927 and emittance (ε) of 0.2. The performance of the coatings at high temperature after heating in air in the range of 25–300 °C for different durations was also investigated. The performance and structure of the CNT/ITO coating was also compared with the wet deposition method in which the ITO coating was formed by spraying.