No abstract

No abstract

No abstract

No abstract

Recently, the supercapacitor has been used as a type of energy storage application. In this work, cobalt hydroxide adorned with nitrogen-doped carbon dots (NC) is synthesized by a hydrothermal approach. Then Co(OH)2/NC is modified by sodium sulfide to obtain S-Co(OH)2/NC, which shows an excellent specific capacitance of 730 F g− 1 at 1 A g− 1 (much higher than that of pristine Co(OH)2/NC (592 F g− 1 at 1 A g− 1)). An asymmetric supercapacitor (ASC) is assembled by S-Co(OH)2/NC (as a positive electrode) and GA/NC (as a negative electrode), which presents a specific energy density as high as 39.59 Wh kg− 1 with a power density of 639 W kg− 1. Also, the ACS manifests extraordinary cycle stability (75% capacitance retention after 8500 cycles). According to the electrochemical performance, it can be inferred that S-Co(OH)2/NC has a great practical application value in supercapacitor devices.

Ethylene‐vinyl acetate copolymer (EVA) has been widely used for packaging materials for decades. However, EVA was highly restricted due to the poor thermal stability and anti‐static performance. For enhancing thermal stability and anti‐static performances, a large number of additives were added to EVA, which seriously prejudice the processability and mechanical properties of the polymer. To address this problem, N‐doped reduced graphene oxide@Fe2O3 (RGF) was constructed as a heat and electronic conduction actor in EVA matrix in this work. As as‐prepared RGF composites shown, Fe2O3 particles well dispersed on the surface of RGO sheets, forming a point‐plane three‐dimensional structure. Therefore, the thermal conductivity and volume resistivity of the EVA composites reached 0.58 W/mK and 1.7 × 1010 ohm∙cm at 1.0 wt.% of RGF addition, which shows 284% folds increasement and 7 orders of magnitude decrement than neat EVA. Moreover, the storage modulus and thermal stability of EVA composites at 180°C were also improved. In sum, all those enhancements were attributed to the Fe2O3 particles well dispersed on RGO sheets, and amino groups from RGF provided mass of hydrogen bonds with EVA chains which provide more sites and path for heat and electronic conduction. In this work, RGF composites and its synthesis strategy show potential promising in the highly effective thermal and electrical exchange materials.

No abstract