Metal–metal battery bears great potential for next-generation large-scale energy storage system because of its simple manufacture process and low production cost.However,the cross-over of metal cations from the catho...Metal–metal battery bears great potential for next-generation large-scale energy storage system because of its simple manufacture process and low production cost.However,the cross-over of metal cations from the cathode to the anode causes a loss in capacity and influences battery stability.Herein,a coating of poly(ionic liquid)(PIL)with poly(diallyldimethylammonium bis(trifluoromethanesulfonyl)imide)(PDADMA^(+)TFSI^(−))on a commercial polypropylene(PP)separator serves as an anion exchange membrane for a 3.3 V copper–lithium battery.The PIL has a positively charged polymer backbone that can block the migration of copper ions,thus improving Coulombic efficiency,long-term cycling stability and inhibiting self-discharge of the battery.It can also facilitate the conduction of anions through the membrane and reduce polarization,especially for fast charging/discharging.Bruce-Vincent method gives the transport number in the electrolyte to be 0.25 and 0.04 for PP separator without and with PIL coating,respectively.This suggests that the PIL layer reduces the contribution of the internal current due to cation transport.The use of PIL as a coating layer for commercial PP separator is a cost-effective way to improve overall electrochemical performance of copper–lithium batteries.Compared to PP and polyacrylic acid(PAA)/PP separators,the PIL/PP membrane raises the Coulombic efficiency to 99%and decreases the average discharge voltage drop to about 0.09 V when the current density is increased from 0.1 to 1 mA cm^(−2).展开更多
In this study,a novel Mg production process for producing high-purity Mg metal from dolomite was developed.When the electrolysis of calcined dolomite was conducted using Cu cathode and C anode in MgF_(2)–LiF molten s...In this study,a novel Mg production process for producing high-purity Mg metal from dolomite was developed.When the electrolysis of calcined dolomite was conducted using Cu cathode and C anode in MgF_(2)–LiF molten salt at 1083–1173 K by applying an average current of 1.42–1.46 A for 9.50–21.0 h,the current efficiency of 66.4–88.6%was obtained.The produced Mg alloys consisted of MgCu_(2)and Cu(Mg)or MgCu_(2)and CuMg_(2)phases,depending on the Mg concentration in the Mg alloy.When the electrolysis of calcined dolomite was conducted in MgF_(2)–LiF–CaF_(2)molten salt at 1083 K,the current efficiency was 40.9–71.4%,owing to undesired reactions such as electroreduction of Ca^(2+)or/and CO_(3)^(2−)ions.Meanwhile,the current efficiency increased from 40.9%to 63.2%by utilizing a Pt anode,because the occurrence of CO_(3)^(2−)ions in the molten salt was prevented.After vacuum distillation of the obtained Mg alloys at 1300 K for 10 h,Mg metal with a purity of 99.9996–99.9998%was produced.Therefore,the feasibility of this novel process for the production of high-purity Mg metal from dolomite was demonstrated.展开更多
The copper cathode ablation limits the maximum power and operating time of arc heaters significantly.In this work,copper cathodes were tested in an ablation testing system to investigate the ablation behaviors and mec...The copper cathode ablation limits the maximum power and operating time of arc heaters significantly.In this work,copper cathodes were tested in an ablation testing system to investigate the ablation behaviors and mechanism of copper cathode in air.The microstructure of the ablated cathodes was analyzed,and the ablation rate was measured.The maximum depth and ablation rate increased with the electronic discharge.The mean ablation rate was compared with the prediction by a thermophysical theoretical model.Many ablation pits formed in the ablated surface and evolved into crater-like structures with unexpected depth as the ablation time was prolonged.The presence of ablation pits and crater-like structures suggested an inhomogeneous ablation behavior of the copper cathode in air.The underlying mechanism is proposed to explain the ablation failure of copper cathode in the high-power arc heater.Future attention to improving the service life of copper cathode could be focused on the surface modification to reduce the ablation inhomogeneity.展开更多
In the morning of August 20,Heilongjiang Zijin Copper Project formally signed agreement at Fularji District in Qiqihar City.This also signals that the copper smelting project with a total investment of 4 billion yuan,...In the morning of August 20,Heilongjiang Zijin Copper Project formally signed agreement at Fularji District in Qiqihar City.This also signals that the copper smelting project with a total investment of 4 billion yuan,a project under planning since 2011,has formally landed in Qiqihar City.展开更多
基金supported by grant from the Research Grants Council(City U 11305220)of the Hong Kong Special Administrative Region,China
文摘Metal–metal battery bears great potential for next-generation large-scale energy storage system because of its simple manufacture process and low production cost.However,the cross-over of metal cations from the cathode to the anode causes a loss in capacity and influences battery stability.Herein,a coating of poly(ionic liquid)(PIL)with poly(diallyldimethylammonium bis(trifluoromethanesulfonyl)imide)(PDADMA^(+)TFSI^(−))on a commercial polypropylene(PP)separator serves as an anion exchange membrane for a 3.3 V copper–lithium battery.The PIL has a positively charged polymer backbone that can block the migration of copper ions,thus improving Coulombic efficiency,long-term cycling stability and inhibiting self-discharge of the battery.It can also facilitate the conduction of anions through the membrane and reduce polarization,especially for fast charging/discharging.Bruce-Vincent method gives the transport number in the electrolyte to be 0.25 and 0.04 for PP separator without and with PIL coating,respectively.This suggests that the PIL layer reduces the contribution of the internal current due to cation transport.The use of PIL as a coating layer for commercial PP separator is a cost-effective way to improve overall electrochemical performance of copper–lithium batteries.Compared to PP and polyacrylic acid(PAA)/PP separators,the PIL/PP membrane raises the Coulombic efficiency to 99%and decreases the average discharge voltage drop to about 0.09 V when the current density is increased from 0.1 to 1 mA cm^(−2).
基金supported by the National Research Councile of Science and Technology funded by the Korean Ministry of Industry in Korea(Project Nos.:1711173260,22-3803)the Korea Evaluation Institute of Industrial Technology funded by the Korean Ministry of Industry in Korea(Project Nos.:1415179713,20011157).
文摘In this study,a novel Mg production process for producing high-purity Mg metal from dolomite was developed.When the electrolysis of calcined dolomite was conducted using Cu cathode and C anode in MgF_(2)–LiF molten salt at 1083–1173 K by applying an average current of 1.42–1.46 A for 9.50–21.0 h,the current efficiency of 66.4–88.6%was obtained.The produced Mg alloys consisted of MgCu_(2)and Cu(Mg)or MgCu_(2)and CuMg_(2)phases,depending on the Mg concentration in the Mg alloy.When the electrolysis of calcined dolomite was conducted in MgF_(2)–LiF–CaF_(2)molten salt at 1083 K,the current efficiency was 40.9–71.4%,owing to undesired reactions such as electroreduction of Ca^(2+)or/and CO_(3)^(2−)ions.Meanwhile,the current efficiency increased from 40.9%to 63.2%by utilizing a Pt anode,because the occurrence of CO_(3)^(2−)ions in the molten salt was prevented.After vacuum distillation of the obtained Mg alloys at 1300 K for 10 h,Mg metal with a purity of 99.9996–99.9998%was produced.Therefore,the feasibility of this novel process for the production of high-purity Mg metal from dolomite was demonstrated.
基金This work was supported by the National Key R&D Program of China(Grant No.2017YFB1200800)the National Natural Science Foundation of China(Grant Nos.11725210,51827810,51637009 and 11572281)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2018XZZX001-05)the National Student′s Platform for Innovation and Entrepreneurship Training Program(Grant No.201910335115).
文摘The copper cathode ablation limits the maximum power and operating time of arc heaters significantly.In this work,copper cathodes were tested in an ablation testing system to investigate the ablation behaviors and mechanism of copper cathode in air.The microstructure of the ablated cathodes was analyzed,and the ablation rate was measured.The maximum depth and ablation rate increased with the electronic discharge.The mean ablation rate was compared with the prediction by a thermophysical theoretical model.Many ablation pits formed in the ablated surface and evolved into crater-like structures with unexpected depth as the ablation time was prolonged.The presence of ablation pits and crater-like structures suggested an inhomogeneous ablation behavior of the copper cathode in air.The underlying mechanism is proposed to explain the ablation failure of copper cathode in the high-power arc heater.Future attention to improving the service life of copper cathode could be focused on the surface modification to reduce the ablation inhomogeneity.
文摘In the morning of August 20,Heilongjiang Zijin Copper Project formally signed agreement at Fularji District in Qiqihar City.This also signals that the copper smelting project with a total investment of 4 billion yuan,a project under planning since 2011,has formally landed in Qiqihar City.
