This paper focuses on the development of three types of activated carbon （AC） adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite （ENG）. Their the...This paper focuses on the development of three types of activated carbon （AC） adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite （ENG）. Their thermal conductivity was investigated with the steady-state heat source method and the permeability was tested with nitrogen as the gas source. Results show that the thermal conductivity of granular AC with different sizes al-most maintains a constant at 0.36 W-（m.K）-＇, while the value modestly increases to 0.40 W.（m.K）-＇ for the con- solidated AC with chemical binder. The consolidated AC with ENG at the density of 600 kg. m-3 shows the best heat transfer performance and their thermal conductivity vary from 2.08 W-（m.K）- to 2.61 W. （m.K）-1 according toits fraction of AC. However, the granular AC and consolidated AC with chemical binder show the better permeabil- ity performance than consolidated AC with ENG binder whose permeability changes from 6.98x10-13 m2 to 5.16x10TM m2 and the maximum occurs when the content of AC reaches 71.4% （by mass）. According to the differ- ent thermal properties, the refrigeration application of three types of adsorbents is analyzed.展开更多
Novel inexpensive, light, flexible, and even rollup or wearable devices are required for multi-functional portable electronics and developing new versatile and flexible electrode materials as alternatives to the mater...Novel inexpensive, light, flexible, and even rollup or wearable devices are required for multi-functional portable electronics and developing new versatile and flexible electrode materials as alternatives to the materials used in contemporary batteries and supercapacitors is a key challenge. Here, binder-free activated carbon （AC）/carbon nanotube （CNT） paper electrodes for use in advanced supercapacitors have been fabricated based on low-cost, industrial-grade aligned CNTs. By a two-step shearing strategy, aligned CNTs were dispersed into individual long CNTs, and then 90 wt%-99 wt% of AC powder was incorporated into the CNT pulp and the AC/CNT paper electrode was fabricated by deposition on a filter. The specific capacity, rate performance, and power density of the AC/CNT paper electrode were better than the corresponding values for an AC/acetylene black electrode. The capacity reached a maximum value of 267.6 F/g with a CNT loading of 5 wt%, and the energy density and power density were 22.5 W.h/kg and 7.3 kW/kg at a high current density of 20 A/g. The AC/CNT paper electrode also showed a good cycle performance, with 97.5% of the original capacity retained after 5000 cycles at a scan rate of 200 mV/s. This method affords not only a promising paper-like nanocomposite for use in low-cost and flexible supercapacitors, but also a general way of fabricating multi-functional paper-like CNT-based nanocomposites for use in devices such as flexible lithium ion batteries and solar cells.展开更多
基金Supported by the National Science Foundation for Excellent Young Scholars （51222601）, the International Collaborating Project Funded by the Foundation of Science and Technology Commission of Shanghai Municipality （11160706000）, the Program for New Century Excellent Talents in University by the Ministry of Education of China and the Shanghai Pujiang Program of China.
文摘This paper focuses on the development of three types of activated carbon （AC） adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite （ENG）. Their thermal conductivity was investigated with the steady-state heat source method and the permeability was tested with nitrogen as the gas source. Results show that the thermal conductivity of granular AC with different sizes al-most maintains a constant at 0.36 W-（m.K）-＇, while the value modestly increases to 0.40 W.（m.K）-＇ for the con- solidated AC with chemical binder. The consolidated AC with ENG at the density of 600 kg. m-3 shows the best heat transfer performance and their thermal conductivity vary from 2.08 W-（m.K）- to 2.61 W. （m.K）-1 according toits fraction of AC. However, the granular AC and consolidated AC with chemical binder show the better permeabil- ity performance than consolidated AC with ENG binder whose permeability changes from 6.98x10-13 m2 to 5.16x10TM m2 and the maximum occurs when the content of AC reaches 71.4% （by mass）. According to the differ- ent thermal properties, the refrigeration application of three types of adsorbents is analyzed.
基金This study was supported by the National Natural Science Foundation of China （Nos. 20736004, 20736007, and 2007AA03Z346）, and the China National Program （No. 2011CB932602）.
文摘Novel inexpensive, light, flexible, and even rollup or wearable devices are required for multi-functional portable electronics and developing new versatile and flexible electrode materials as alternatives to the materials used in contemporary batteries and supercapacitors is a key challenge. Here, binder-free activated carbon （AC）/carbon nanotube （CNT） paper electrodes for use in advanced supercapacitors have been fabricated based on low-cost, industrial-grade aligned CNTs. By a two-step shearing strategy, aligned CNTs were dispersed into individual long CNTs, and then 90 wt%-99 wt% of AC powder was incorporated into the CNT pulp and the AC/CNT paper electrode was fabricated by deposition on a filter. The specific capacity, rate performance, and power density of the AC/CNT paper electrode were better than the corresponding values for an AC/acetylene black electrode. The capacity reached a maximum value of 267.6 F/g with a CNT loading of 5 wt%, and the energy density and power density were 22.5 W.h/kg and 7.3 kW/kg at a high current density of 20 A/g. The AC/CNT paper electrode also showed a good cycle performance, with 97.5% of the original capacity retained after 5000 cycles at a scan rate of 200 mV/s. This method affords not only a promising paper-like nanocomposite for use in low-cost and flexible supercapacitors, but also a general way of fabricating multi-functional paper-like CNT-based nanocomposites for use in devices such as flexible lithium ion batteries and solar cells.
