Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activ...Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.展开更多
A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resultin...A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resulting in significantly enhanced activity and reversibility towards VO2^+/VO2^+ and V^2+/V3^+couples. VFB with PGF electrode demonstrates outstanding performance such as high-rate capability under 50–400 mA cm^-2, wide-temperature tolerance at-20 °C–60 °C, and excellent durability over 1000 charge–discharge cycles. These merits enable PGF a promising electrode for the next-generation VFB,which can operate at high-power and all-climate conditions.展开更多
The electrode is one of the main components in redox flow batteries(RFBs), as it provides the reactions sites for redox couples and can influence the cell performance through its effect on cell voltage losses associat...The electrode is one of the main components in redox flow batteries(RFBs), as it provides the reactions sites for redox couples and can influence the cell performance through its effect on cell voltage losses associated with activation overpotential, concentration overpotential and ohmic losses. Extensive research has thus been carried out on material selection, structural design and modification of electrodes as well as electrocatalysis for redox reactions. This review provides an historical overview of the screening and modification of electrode materials together with recent progress in novel electrode architectures, electrode modification and electrocatalysis methods. RFB systems such as iron/chromium, polysulfide/bromine and all vanadium batteries are discussed in detail.展开更多
A mild and simple synthesis process for large-scale vanadium redox flow batteries(VRFBs)energy storage systems is desirable.A graphite felt/Mn O_2(GF-MNO)composite electrode with excellent electrocatalytic activity to...A mild and simple synthesis process for large-scale vanadium redox flow batteries(VRFBs)energy storage systems is desirable.A graphite felt/Mn O_2(GF-MNO)composite electrode with excellent electrocatalytic activity towards VO^(2+)/VO_2^+redox couples in a VRFB was synthesized by a one-step hydrothermal process.The resulting GF-MNO electrodes possess improved electrochemical kinetic reversibility of the vanadium redox reactions compared to pristine GF electrodes,and the corresponding energy efficiency and discharge capacity at 150 m A cm^(-2)are increased by 12.5%and 40%,respectively.The discharge capacity is maintained at 4.8 A h L^(-1)at the ultrahigh current density of 250 m A cm^(-2).Above all,80%of the energy efficiency of the GF-MNO composite electrodes is retained after 120 charge-discharge cycles at 150 m A cm^(-2).Furthermore,these electrodes demonstrated that more evenly distributed catalytic active sites were obtained from the Mn O_2particles under acidic conditions.The proposed synthetic route is facile,and the raw materials are low cost and environmentally friendly.Therefore,these novel GF-MNO electrodes hold great promise in large-scale vanadium redox flow battery energy storage systems.展开更多
基金financial support from the National Natural Science Foundation of China (No. 21576154)the Open Fund of The State Key Laboratory of Refractories and Metallurgy (No. G201809)the Shenzhen Basic Research Project (Nos. JCYJ20170412170756603 and JCYJ20170307152754218)
文摘Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.
基金supported by the National Natural Science Foundation of China(No.21576154)the Shenzhen Basic Research Project(Nos.JCYJ20170818115018000,JCYJ20170307154206288,JCYJ20170412170756603)
文摘A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resulting in significantly enhanced activity and reversibility towards VO2^+/VO2^+ and V^2+/V3^+couples. VFB with PGF electrode demonstrates outstanding performance such as high-rate capability under 50–400 mA cm^-2, wide-temperature tolerance at-20 °C–60 °C, and excellent durability over 1000 charge–discharge cycles. These merits enable PGF a promising electrode for the next-generation VFB,which can operate at high-power and all-climate conditions.
文摘The electrode is one of the main components in redox flow batteries(RFBs), as it provides the reactions sites for redox couples and can influence the cell performance through its effect on cell voltage losses associated with activation overpotential, concentration overpotential and ohmic losses. Extensive research has thus been carried out on material selection, structural design and modification of electrodes as well as electrocatalysis for redox reactions. This review provides an historical overview of the screening and modification of electrode materials together with recent progress in novel electrode architectures, electrode modification and electrocatalysis methods. RFB systems such as iron/chromium, polysulfide/bromine and all vanadium batteries are discussed in detail.
基金supported by the Ministry of Science and Technology of China (2016YFA0202500)the National Natural Science Foundation of China (51772093)the National key Research and Development Program of China (2017YFD0301507)
文摘A mild and simple synthesis process for large-scale vanadium redox flow batteries(VRFBs)energy storage systems is desirable.A graphite felt/Mn O_2(GF-MNO)composite electrode with excellent electrocatalytic activity towards VO^(2+)/VO_2^+redox couples in a VRFB was synthesized by a one-step hydrothermal process.The resulting GF-MNO electrodes possess improved electrochemical kinetic reversibility of the vanadium redox reactions compared to pristine GF electrodes,and the corresponding energy efficiency and discharge capacity at 150 m A cm^(-2)are increased by 12.5%and 40%,respectively.The discharge capacity is maintained at 4.8 A h L^(-1)at the ultrahigh current density of 250 m A cm^(-2).Above all,80%of the energy efficiency of the GF-MNO composite electrodes is retained after 120 charge-discharge cycles at 150 m A cm^(-2).Furthermore,these electrodes demonstrated that more evenly distributed catalytic active sites were obtained from the Mn O_2particles under acidic conditions.The proposed synthetic route is facile,and the raw materials are low cost and environmentally friendly.Therefore,these novel GF-MNO electrodes hold great promise in large-scale vanadium redox flow battery energy storage systems.
