Xiaohui Jiang

Large scale production of polyacrylonitrile-based Porous Carbon Nanospheres for Asymmetric Supercapacitors

The increasing demand for a satisfactory combination of energy–power features in supercapacitors has triggered considerable research efforts dedicated to the development of high-efficiency energy storage devices. In our study, highly cross-linked porous carbon microspheres were prepared via the carbonization of as-prepared polymer spheres followed by a KOH activation process. The resultant products exhibited a high maximum specific surface area (3065.6 m2 g−1), rich nitrogen and oxygen doping (22.3 wt%) and a significant volume fraction of mesopores/macropores (37.91%). The optimal electrode presents the highest specific capacitance of 290 F g−1 and superior cycling stability with 96% retention after 3000 cycles in an aqueous 2 M KOH electrolyte. Moreover, the assembled asymmetric supercapacitor device based on Co0.9Mn0.1 arrays as the positive electrode achieves a specific capacitance of 105.43 F g−1 and an energy density of 134.9 W h kg−1 at a power density of 2879.8 W kg−1. Interestingly, the device can illuminate an LED for 30 min, demonstrating the promising application potential in high-performance devices related to energy storage.

Synthesis and properties of an acrylamide-based polymer for enhanced oil recovery: A preliminary study

Fossil fuels currently supply more than 85% of the world’s energy, and the global energy demand and consumption is forecasted to increase rapidly over the next 20 years.[1] Such demand can only be satisfied by sustaining the production of energy in existing fields. Therefore, enhanced oil recovery (EOR) from existing fields has become increasingly important. EOR methods are fieldproven techniques that improve the efficiency and effectiveness of oil recovery.[2–4] Figure 1a shows the China oil volume distribution in 2013. Therein, the polymer flooding method is considered one of the most promising chemical EOR processes in many reservoirs because of its low cost and efficient recovery of more than 10% oil over water flooding.[5] Moreover, Meng et al[6] also confirmed that polymer flooding can increase displacement efficiency. However, traditional polymer flooding is not recommended for heavy oil reservoirs because of its large disparity with oil viscosity according to the screen criteria.[7] Partially hydrolyzed polyacrylamide (HPAM) and biopolymer (xanthan gum) are the most commonly used EOR polymers in practice, especially HPAM.[8] However, HPAM is prone to microbial degradation and shows extreme sensitivity to salt and temperature. As a new watersoluble polymer, hydrophobically associating polymer solves the disadvantages of HPAM by grafting short hydrophobic side chains.[9,10] Shashkina et al[11] investigated the hydrophobic aggregation in aqueous solutions of hydrophobically modified polyacrylamide in the vicinity of critical association concentration. In light of the results of the recovery, oil field wastewater must be used in polymer flooding, but the high salinity, high temperature, and high bacterial content in the wastewater may cause polymer degradation, molecular chain curling, and loss of solution viscosity.[8,12] Sulfatereducing and saprophytic monocytogenes bacteria can persist and adhere to the pipe wall to contact with the continuous injection of polymer. Coupled with the dark and humid underground environment, these bacteria will seriously corrode and block Received: 10 December 2017 | Accepted: 18 January 2018 DOI: 10.1002/adv.21949