Supercapacitors have a rapid charge/discharge rate, long lifespan, high stability, and relatively acceptable cost, showing great potential in energy storage and conversion applications. However, the current cost-effective carbon-based electrodes have limited application owing to their low specific capacitance and unsatisfactory stability. In this regard, we herein prepare nitrogen-doped carbons by carbonizing a mixture of cotton pulp (CCP) and melamine to improve the specific capacitance by integrating pore (mesopore) and surface (oxygen-containing groups) modification with defect engineering via the carbonization process. Furthermore, the structural and morphological features of the resultant nitrogen-doped carbons are confirmed by various characterization techniques. Excitingly, the specific capacitance for nitrogen-doped CCP (CCPN1) with a 1 : 1 weight ratio of CCP and melamine is 642 F g−1 at a current density of 0.5 A g−1 in a three-electrode system, surpassing that of the reported carbon analogues and most metal-based materials to date. The stability test suggests that the specific capacitance of CCPN1 is maintained over 150 F g−1 at a current density of 2 A g−1 even over 5000 cycles. Therefore, the reported nitrogen-doped carbons from cotton pulp exhibit improved specific capacitance and stability, providing a new cost-effective carbon-based material for application in the energy storage field.
Huan Liu,Bo Pang,Jinghui Zhou,Ying Han,Jie Lu,Haiming Li,Haisong Wang
Black liquor is a significant water pollution source, and many investigations related to black liquor have been performed over the years. Recovering cotton pulping black liquor (CPBL) is difficult due to its low lignin content. This study presents corn stover pretreatments using CPBL alone and in combination with other agents to improve the cost-effectiveness of the biomass-to-sugar conversion. The results showed that 78.4%, 74.9% and 82.1% of the lignin was removed after pretreatment with sodium hydroxide (SHP), CPBL (CPBLP) and CPBL combined with sodium sulfite (SS-CPBLP). Accordingly, the glucose and xylose contents in the pretreated corn stover increased to more than 62% and 24% after CPBLP and SS-CPBLP, respectively, which was comparable to SHP. Moreover, the total sugar yield of CPBLP and SS-CPBLP was 66.4% and 75.3%, which was 2.9% and 11.8% higher than that of SHP (63.5%), respectively. The lignin content in the black liquor rose from 6.9 g/L to 17.8 g/L, and the sulfonation degree of the black liquor reached 0.8 mmol/g after SS-CPBLP, which had a positive effect on further lignin utilization. The results indicate that the use of CPBL for corn stover pretreatment not only efficiently produced fermentable sugar products, but also presented a solution to the CPBL pollution issue. Thus, this process represents a method of waste recycling with high industrialization potential.
危险品化学品经营许可证（带存储）