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The rechargeable aqueous zinc–iodine (Zn–I2) battery has emerged as a promising electrochemical energy storage technology. However, poor cycling stability caused by the dissolution of iodine species into the electrolyte limited its practical application. Herein, we report a nitrogen-doped porous carbon (NPC) material in gram scales. Performed as an iodine host in the Zn–I2 battery, the NPC shows a high specific capacity (345.3 mAh g–1 at 0.2 C), superior rate capability (53.2% capacity retention at 10 C), and remarkable cycling stability (10 000 cycles at 10 C with a capacity retention of 80.9%). More importantly, DFT computations reveal that the graphitic-N (N-Q) exhibits the strongest adsorption of iodine; however, pyridinic-N (N-6) shows the weakest adsorption of iodine. Moreover, the N-6/N-Q ratio is an essential parameter that significantly determined the electrochemical performance of Zn–I2 batteries. Therefore, the improved long-term cycling stability and rate capability of the as-designed Zn–I2 battery are attributable to the decrease of the N-6/N-Q ratio. This work is of great significance for devolving highly reversible Zn–I2 batteries.

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Thermal depolymerisation induced tracking and erosion of polymeric insulators is one of the key insulation failure modes and this process adversely affects the reliability of power delivery networks. This study reports the tracking, erosion and thermal distribution of micron-AlN and micron-AlN + nano-SiO 2 co-filled silicone rubber composites. A tracking-erosion model is presented to explain how the co-filled set of particles directly affects such mechanisms. Aluminium nitride (AlN: 5-10 μm) and silica (SiO 2 : 20 nm) particles were procured for fabricating test samples. The inclined plane test according to IEC 60587 was carried out using tracking voltage method 2 with an initial applied voltage of 3 kV and a ramping rate of 0.25 kV/h over the duration of 240 min. Measurement results show co-filled composites exhibit significantly lower physical tracking and erosion as compared to micron-AlN filled composites. Thermal accumulation and average leakage current in co-filled composites are found noticeably lower than micron-filled counterparts. Moreover, the increased surface area of the combined co-filled particles in the composites provides better scattering and reduce secondary electron collision. This may impede the release of high energy causing thermal degradation.

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