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Re: Microvast ultrafast charge station for electric buses begins operation in Chongqi
That's the future right there. Nanotechnologies are being researched and develop all over the major industry players of the world.
That's the future right there. Nanotechnologies are being researched and develop all over the major industry players of the world.
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News on China's scientific and technological development
Sandwich-like MnO2/Mn/MnO2 nanotube array shows high supercapacitive performance
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28 June 2012
Researchers at Sun Yat-sen University in Guangzhou, China designed and synthesized novel MnO2/Mn/MnO2 sandwich-like nanotube arrays for supercapacitors. In testing reported in the ACS journal Nano Letters, the hybrid MnO2/Mn/MnO2 sandwich-like nanotube arrays exhibited an excellent rate capability with a high specific energy of 45 Wh/kg and specific power of 23 kW/kg and excellent long-term cycling stability (less 5% loss of the maximum specific capacitance after 3,000 cycles).
The high specific capacitance and charge−discharge rates offered by the sandwich-like nanotube arrays make them promising candidates for supercapacitor electrodes, combining high-energy densities with high levels of power delivery, the researchers suggest.
Supercapacitors—also called ultracapacitors or electrochemical capacitors (ECs)—offer high power density, fast charging−discharging rate, and excellent cycle stability. Various materials, including carbon materials, transition-metal oxides, conducting polymers, and hybrid composites have been widely studied as electrodes for these devices, the team notes.
Li2
Left. Ragone plots (energy density vs power density): (1) MnO2/Mn/MnO2 SNTAs and (2) MnO2 NTAs. Right. Comparison of cycling performance of (1) and (2) for 3000 cycles at 1.5 A/g. (The specific mass loading is 0.32 mg/cm2). Credit: ACS, Li et al.Click to enlarge.
There has been extensive interest in developing the inexpensive transition-metal oxide electrodes, such as MnO2, Co3O4, NiO, VOx, and TiO2 for supercapacitors. MnO2 is an attractive electrode material owing to its high theoretical specific capacitance, low cost, natural abundance, and environmental friendliness. However, poor electrical conductivity (10−5∼10−6 S/cm) remains a major challenge and limits rate capability for high power performance.
Recent work has explored possible solutions such as hybrid composite nanostructures in which thin MnO2 layers were loaded on highly conductive materials such as metal, conducting polymer, carbon nanotube, or graphene for enhanced performance.
The enhanced performance was also obtained by coating MnO2 onto SnO2 nanowires, ZnO nanorods, and Zn2SnO4 nanowires. In all of the above cases, MnO2 is of relatively low weight fraction and usually has excellent rate and cycling performance; however, the energy and power densities of electrodes are sacrificed.
To realize the practical applications for high-performance ECs that needs large capacitance and high energy storage, here we design and synthesize novel MnO2/Mn/MnO2 sandwich-structured nanotube arrays (SNTAs) with high MnO2 weight fraction...The aligned SNTAs represent a new prime example of materials with a well-defined pore structure.
—Li et al.
The team outlined four primary reasons for taking this approach:
The middle crystalline metal Mn layer in the sandwich provides electron “superhighways”—highly conductive cores—for charge storage and delivery, which overcomes the key weakness (the limited electric conductivity) of MnO2.
The MnO2/Mn/MnO2 SNTAs relax the transport of ions because of the hollow nanostructures. In addition, the double thin layers of MnO2 in SNTAs would enable fast, reversible Faradaic reactions and provide short ion diffusion paths.
The SNTAs with double MnO2 shells would obviously enhance the utilization rate of MnO2 material because of anisotropic morphology, large specific surface area, and hollow nanostructures.
The SNTAs directly growing on conductive substrate have an excellent electrical contact with current collectors, and this would let each MnO2/Mn/MnO2 nanotube effectively participate in electrochemical reactions with almost no “dead” volume.
The maximum specific capacitances of 937 F/g at a scan rate of 5 mV/s by cyclic voltammetry (CV) and 955 F/g at a current density of 1.5 A/g by chronopotentiometry were achieved for the MnO2/Mn/MnO2 sandwich-like nanotube arrays in solution of 1.0 M Na2SO4.
Resources
Qi Li, Zi-Long Wang, Gao-Ren Li, Rui Guo, Liang-Xin Ding, and Ye-Xiang Tong (2012) Design and Synthesis of MnO2/Mn/MnO2 Sandwich-Structured Nanotube Arrays with High Supercapacitive Performance for Electrochemical Energy Storage. Nano Letters doi: 10.1021/nl301748m
Comments
This sounds like a marriage made in heaven with fuel cells.
2-3 kgs of these and the surge in energy needed for braking is covered, as is regenerative braking.
Posted by: Davemart | June 28, 2012 at 04:39 AM
S/be 'energy needed for acceleration'
Posted by: Davemart | June 28, 2012 at 04:43 AM
As with other supercapacitors we've been reading about lately, the performance is there and now it is just a question of cost.
Posted by: Engineer-Poet | June 28, 2012 at 06:22 AM
I have no idea what the final costs will be, but the materials at least are cheap enough.
Posted by: Davemart | June 28, 2012 at 06:26 AM
Wait, asides of the beauty of the results that makes these supercapacitors battery like, how do they grow the nanotube ? with some CVD or epitaxy then this won't be used for anything else than powering a cell phone at very best. Nanotube are extensively studied but there is still no manufacturing tool to make them in volume as far as I am informed
Posted by: Treehugger | June 28, 2012 at 07:03 AM
Yes DM ... it would be an ideal companion for FC equipped vehicles or for BEVs equipped with very high energy density batteries.
Cost, like for most new technologies, will come down with mass production in the right place.
Posted by: HarveyD | June 28, 2012 at 07:23 AM
Sandwich-like MnO2/Mn/MnO2 nanotube array shows high supercapacitive performance
-----------------------------------------------------------------------------------
28 June 2012
Researchers at Sun Yat-sen University in Guangzhou, China designed and synthesized novel MnO2/Mn/MnO2 sandwich-like nanotube arrays for supercapacitors. In testing reported in the ACS journal Nano Letters, the hybrid MnO2/Mn/MnO2 sandwich-like nanotube arrays exhibited an excellent rate capability with a high specific energy of 45 Wh/kg and specific power of 23 kW/kg and excellent long-term cycling stability (less 5% loss of the maximum specific capacitance after 3,000 cycles).
The high specific capacitance and charge−discharge rates offered by the sandwich-like nanotube arrays make them promising candidates for supercapacitor electrodes, combining high-energy densities with high levels of power delivery, the researchers suggest.
Supercapacitors—also called ultracapacitors or electrochemical capacitors (ECs)—offer high power density, fast charging−discharging rate, and excellent cycle stability. Various materials, including carbon materials, transition-metal oxides, conducting polymers, and hybrid composites have been widely studied as electrodes for these devices, the team notes.
Li2
Left. Ragone plots (energy density vs power density): (1) MnO2/Mn/MnO2 SNTAs and (2) MnO2 NTAs. Right. Comparison of cycling performance of (1) and (2) for 3000 cycles at 1.5 A/g. (The specific mass loading is 0.32 mg/cm2). Credit: ACS, Li et al.Click to enlarge.
There has been extensive interest in developing the inexpensive transition-metal oxide electrodes, such as MnO2, Co3O4, NiO, VOx, and TiO2 for supercapacitors. MnO2 is an attractive electrode material owing to its high theoretical specific capacitance, low cost, natural abundance, and environmental friendliness. However, poor electrical conductivity (10−5∼10−6 S/cm) remains a major challenge and limits rate capability for high power performance.
Recent work has explored possible solutions such as hybrid composite nanostructures in which thin MnO2 layers were loaded on highly conductive materials such as metal, conducting polymer, carbon nanotube, or graphene for enhanced performance.
The enhanced performance was also obtained by coating MnO2 onto SnO2 nanowires, ZnO nanorods, and Zn2SnO4 nanowires. In all of the above cases, MnO2 is of relatively low weight fraction and usually has excellent rate and cycling performance; however, the energy and power densities of electrodes are sacrificed.
To realize the practical applications for high-performance ECs that needs large capacitance and high energy storage, here we design and synthesize novel MnO2/Mn/MnO2 sandwich-structured nanotube arrays (SNTAs) with high MnO2 weight fraction...The aligned SNTAs represent a new prime example of materials with a well-defined pore structure.
—Li et al.
The team outlined four primary reasons for taking this approach:
The middle crystalline metal Mn layer in the sandwich provides electron “superhighways”—highly conductive cores—for charge storage and delivery, which overcomes the key weakness (the limited electric conductivity) of MnO2.
The MnO2/Mn/MnO2 SNTAs relax the transport of ions because of the hollow nanostructures. In addition, the double thin layers of MnO2 in SNTAs would enable fast, reversible Faradaic reactions and provide short ion diffusion paths.
The SNTAs with double MnO2 shells would obviously enhance the utilization rate of MnO2 material because of anisotropic morphology, large specific surface area, and hollow nanostructures.
The SNTAs directly growing on conductive substrate have an excellent electrical contact with current collectors, and this would let each MnO2/Mn/MnO2 nanotube effectively participate in electrochemical reactions with almost no “dead” volume.
The maximum specific capacitances of 937 F/g at a scan rate of 5 mV/s by cyclic voltammetry (CV) and 955 F/g at a current density of 1.5 A/g by chronopotentiometry were achieved for the MnO2/Mn/MnO2 sandwich-like nanotube arrays in solution of 1.0 M Na2SO4.
Resources
Qi Li, Zi-Long Wang, Gao-Ren Li, Rui Guo, Liang-Xin Ding, and Ye-Xiang Tong (2012) Design and Synthesis of MnO2/Mn/MnO2 Sandwich-Structured Nanotube Arrays with High Supercapacitive Performance for Electrochemical Energy Storage. Nano Letters doi: 10.1021/nl301748m
Comments
This sounds like a marriage made in heaven with fuel cells.
2-3 kgs of these and the surge in energy needed for braking is covered, as is regenerative braking.
Posted by: Davemart | June 28, 2012 at 04:39 AM
S/be 'energy needed for acceleration'
Posted by: Davemart | June 28, 2012 at 04:43 AM
As with other supercapacitors we've been reading about lately, the performance is there and now it is just a question of cost.
Posted by: Engineer-Poet | June 28, 2012 at 06:22 AM
I have no idea what the final costs will be, but the materials at least are cheap enough.
Posted by: Davemart | June 28, 2012 at 06:26 AM
Wait, asides of the beauty of the results that makes these supercapacitors battery like, how do they grow the nanotube ? with some CVD or epitaxy then this won't be used for anything else than powering a cell phone at very best. Nanotube are extensively studied but there is still no manufacturing tool to make them in volume as far as I am informed
Posted by: Treehugger | June 28, 2012 at 07:03 AM
Yes DM ... it would be an ideal companion for FC equipped vehicles or for BEVs equipped with very high energy density batteries.
Cost, like for most new technologies, will come down with mass production in the right place.
Posted by: HarveyD | June 28, 2012 at 07:23 AM
Equation
Lieutenant General
Re: Microvast ultrafast charge station for electric buses begins operation in Chongqi
What's the significant benefits for the South Pole exploration down in the Antarctica?
What's the significant benefits for the South Pole exploration down in the Antarctica?