氧化錳基納米復合電極材料的制備及其電容特性研究
發(fā)布時間：2018-08-16 14:26
【摘要】：隨著人們生活水平的提高，人們對能源的需求也越來越大，不可再生資源日益枯竭，必然會爆發(fā)能源危機，新能源的開發(fā)和利用是解決能源危機的有效途徑。新能源的開發(fā)與利用明顯離不開能量的存儲，作為高效環(huán)保的儲能元件，超級電容器成為近年來研究的熱點。 超級電容器是兼具高比容量和比功率的高效儲能元件，電極材料的優(yōu)劣直接影響到超級電容器的性能。開發(fā)性能優(yōu)良、環(huán)保價廉的電極材料是超級電容器發(fā)展的方向，當前超級電容器電極材料還存在生產成本高，性能較差的弊端。針對這一點，本文采用微波水熱法，研究了納米氧化錳和納米氧化錳復合電極材料的制備，并對樣品進行表征和電容特性的測試。 采用微波水熱法，以KMnO4為原料，制備了多種形貌（花球狀、空心管、棒狀）的納米MnO2。氧化錳首先生長成由薄片聚集成的花球狀δ-MnO2，隨著時間推移，薄片卷曲成空管狀并從大顆粒中脫落，然后繼續(xù)在空管內部結晶，生長成實心方棒狀的一維α-MnO2。通過將MnO2粉體和作為粘結劑的PEG4000以及作為導電劑的碳粉混合后涂敷在泡沫鎳集流體上制備成電極，并進行電容特性測試。結果表明：125℃下保溫1h制備的包含花球狀和一維管狀形貌的樣品在5mV/s的掃描速率下比電容最大為199.65F/g。但是隨著掃描速率的增大，比電容衰減較快，掃描速率增大到50mV/s時，比電容只保留原來的16%。而125℃下保溫2h制備的一維管狀的樣品在掃描速率為5mV/s下比電容為163.99F/g，掃描速率增大到50mV/s，比電容仍能保持原來的45%。 通過微波水熱法制備了活性碳纖維布負載納米氧化錳的復合電極材料，通過改變反應溫度和保溫時間以及KMnO4濃度，合成出具有不同形貌的的復合材料并對其進行電容測試。結果表明，0.005mol/L KMnO4與ACFC在70℃下保溫1h制備的復合材料為類似草坪的δ-MnO2生長在碳纖維表面，厚度為100~200nm，δ-MnO2呈草葉狀，葉片厚10nm左右，負載量為2.85mg/cm2。在1mol/L的Na2SO4水溶液中，電勢窗口為-0.4~1.5V（vs SCE），掃描速率為5mV/s下，，當反應溫度為70℃，反應時間為0.25h，高錳酸鉀濃度為0.01mol/L，加入2片大小為3cm×3cm的活性碳纖維布時，復合電極的比電容最大，為57.08F/g，且電極內阻較小。 通過微波輻照，利用尿素的還原性，還原氧化石墨烯，添加0.90g尿素在95℃保溫150min可以將15ml濃度為0.25mg/ml氧化石墨烯（GO）完全還原為透明度較高、完整性較好的石墨烯。通過微波水熱法合成了石墨烯與氧化錳的復合材料，將復合材料與作為導電劑的碳納米管以及作為PEG4000作為粘結劑混后涂覆在碳纖維紙上干燥后得到電極。將干燥后的電極作為工作電極，采用三電極系統(tǒng)，測試復合材料的CV曲線以及交流阻抗。結果表明：電極在掃描速率為5mV/s的情況下，測得的電極材料的比電容最大為281F/g；隨著掃描速率的增加其比電容逐漸變小，但掃描速率為50mV/s時，復合材料的比電容仍保留原來的40.6%，為114F/g。
[Abstract]:With the improvement of people's living standards, people's demand for energy is also growing, non-renewable resources are increasingly exhausted, energy crisis will inevitably erupt, the development and utilization of new energy is an effective way to solve the energy crisis. Container has become a hot topic in recent years.
Supercapacitor is an efficient energy storage element with high specific capacity and specific power. The quality of electrode materials directly affects the performance of supercapacitor. The development of electrode materials with good performance and low environmental protection cost is the development direction of supercapacitor. At present, electrode materials of supercapacitor still have the disadvantages of high production cost and poor performance. In this paper, the preparation of nano-manganese oxide and nano-manganese oxide composite electrode materials was studied by microwave hydrothermal method, and the samples were characterized and the capacitance characteristics were tested.
Nano-MnO2 with various morphologies (flower-shaped, hollow tube, rod-shaped) were prepared by microwave hydrothermal method using KMnO_4 as raw material. Manganese oxide first grew into flower-shaped delta-MnO_2 aggregated by thin sheets. Over time, the thin sheets curled into hollow tubes and fell off from the large particles, and then continued to crystallize in the inner part of the hollow tube and grew into a solid square rod-shaped one. Vitamin A-MnO2. The electrode was prepared by mixing MnO2 powder with PEG4000 as binder and carbon powder as conductive agent and coating on nickel foam collector. The capacitance characteristics of the electrode were tested. The results show that the sample with spherical and one-dimensional tubular morphology prepared at 125 C for 1 h has the largest specific capacitance at 5 mV/s scanning rate. However, the specific capacitance decreases rapidly with the increase of scanning rate, and only 16% of the original capacitance is retained when the scanning rate increases to 50 mV/s. The specific capacitance of the one-dimensional tubular sample prepared at 125 C for 2 h at scanning rate of 5 mV/s is 163.99 F/g, the scanning rate increases to 50 mV/s, and the specific capacitance can still keep 45% of the original.
The composite electrode materials loaded with nano-manganese oxide were prepared by microwave hydrothermal method. The composite materials with different morphologies were synthesized by changing reaction temperature, holding time and KMnO_4 concentration, and their capacitance was tested. The results showed that the composite materials prepared by 0.005 mol/L KMnO_4 and ACFC at 70 C for 1 h were prepared. For lawn-like delta-MnO2 grown on the surface of carbon fibers, the thickness of delta-MnO2 was 100-200 nm, the thickness of delta-MnO2 was grass-like, the leaf thickness was about 10 nm, the loading was 2.85 mg/cm2. In Na2SO4 aqueous solution of 1 mol/L, the potential window was - 0.4-1.5 V (vs SCE), the scanning rate was 5 mV/s, when the reaction temperature was 70 c, the reaction time was 0.25 h, the concentration of potassium permanganate was 0.01 mol/L, and the concentration of potassium permanganate was 0.01 mol/L. The specific capacitance of the composite electrode is 57.08F/g and the internal resistance of the electrode is small when two pieces of activated carbon fiber cloth with the size of 3 cm *3 cm are added.
Graphene oxide (GO) with a concentration of 0.25mg/ml can be completely reduced to graphene with high transparency and integrity by microwave irradiation. Graphene and manganese oxide composite materials were synthesized by microwave hydrothermal method. The composite materials were prepared by adding 0.90g urea at 95 C for 150 min. Carbon nanotubes (CNTs) as conductive agent and PEG4000 as binder were mixed and coated on carbon fiber paper for drying. The CV curves and AC impedance of the composites were measured with a three-electrode system using the dried electrode as working electrode. The maximum specific capacitance of the composite is 281 F/g, and the specific capacitance decreases gradually with the increase of scanning rate. However, when the scanning rate is 50 mV/s, the specific capacitance of the composite remains 40.6% and 114 F/g.
【學位授予單位】：濟南大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TQ137.12;TM53
本文編號：2186252
[Abstract]:With the improvement of people's living standards, people's demand for energy is also growing, non-renewable resources are increasingly exhausted, energy crisis will inevitably erupt, the development and utilization of new energy is an effective way to solve the energy crisis. Container has become a hot topic in recent years.
Supercapacitor is an efficient energy storage element with high specific capacity and specific power. The quality of electrode materials directly affects the performance of supercapacitor. The development of electrode materials with good performance and low environmental protection cost is the development direction of supercapacitor. At present, electrode materials of supercapacitor still have the disadvantages of high production cost and poor performance. In this paper, the preparation of nano-manganese oxide and nano-manganese oxide composite electrode materials was studied by microwave hydrothermal method, and the samples were characterized and the capacitance characteristics were tested.
Nano-MnO2 with various morphologies (flower-shaped, hollow tube, rod-shaped) were prepared by microwave hydrothermal method using KMnO_4 as raw material. Manganese oxide first grew into flower-shaped delta-MnO_2 aggregated by thin sheets. Over time, the thin sheets curled into hollow tubes and fell off from the large particles, and then continued to crystallize in the inner part of the hollow tube and grew into a solid square rod-shaped one. Vitamin A-MnO2. The electrode was prepared by mixing MnO2 powder with PEG4000 as binder and carbon powder as conductive agent and coating on nickel foam collector. The capacitance characteristics of the electrode were tested. The results show that the sample with spherical and one-dimensional tubular morphology prepared at 125 C for 1 h has the largest specific capacitance at 5 mV/s scanning rate. However, the specific capacitance decreases rapidly with the increase of scanning rate, and only 16% of the original capacitance is retained when the scanning rate increases to 50 mV/s. The specific capacitance of the one-dimensional tubular sample prepared at 125 C for 2 h at scanning rate of 5 mV/s is 163.99 F/g, the scanning rate increases to 50 mV/s, and the specific capacitance can still keep 45% of the original.
The composite electrode materials loaded with nano-manganese oxide were prepared by microwave hydrothermal method. The composite materials with different morphologies were synthesized by changing reaction temperature, holding time and KMnO_4 concentration, and their capacitance was tested. The results showed that the composite materials prepared by 0.005 mol/L KMnO_4 and ACFC at 70 C for 1 h were prepared. For lawn-like delta-MnO2 grown on the surface of carbon fibers, the thickness of delta-MnO2 was 100-200 nm, the thickness of delta-MnO2 was grass-like, the leaf thickness was about 10 nm, the loading was 2.85 mg/cm2. In Na2SO4 aqueous solution of 1 mol/L, the potential window was - 0.4-1.5 V (vs SCE), the scanning rate was 5 mV/s, when the reaction temperature was 70 c, the reaction time was 0.25 h, the concentration of potassium permanganate was 0.01 mol/L, and the concentration of potassium permanganate was 0.01 mol/L. The specific capacitance of the composite electrode is 57.08F/g and the internal resistance of the electrode is small when two pieces of activated carbon fiber cloth with the size of 3 cm *3 cm are added.
Graphene oxide (GO) with a concentration of 0.25mg/ml can be completely reduced to graphene with high transparency and integrity by microwave irradiation. Graphene and manganese oxide composite materials were synthesized by microwave hydrothermal method. The composite materials were prepared by adding 0.90g urea at 95 C for 150 min. Carbon nanotubes (CNTs) as conductive agent and PEG4000 as binder were mixed and coated on carbon fiber paper for drying. The CV curves and AC impedance of the composites were measured with a three-electrode system using the dried electrode as working electrode. The maximum specific capacitance of the composite is 281 F/g, and the specific capacitance decreases gradually with the increase of scanning rate. However, when the scanning rate is 50 mV/s, the specific capacitance of the composite remains 40.6% and 114 F/g.
【學位授予單位】：濟南大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TQ137.12;TM53
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