掺铋α-MnO_2纳米棒的合成及超电容性能

采用水热法合成了掺铋α-MnO_2纳米棒,通过X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、循环伏安(CV)、恒电流充放电和电化学阻抗谱(EIS)等手段对材料的结构及电化学性能进行了表征.结果表明,铋以Bi~(3+)形式掺杂于α-MnO_2的晶格之中;掺铋α-MnO_2纳米棒的电化学性能比未掺铋α-MnO_2有明显改善,在1 A/g的电流密度下,比电容(265 F/g)比同条件合成的未掺铋α-MnO_2(129 F/g)提高约1.05倍,1 A/g电流密度下循环2000周后容量保持率为95%.     

碳纳米管/聚苯胺/石墨烯复合纳米碳纸及其电化学电容行为

通过真空抽滤的方法制备碳纳米管纸,并对其进行循环伏安电化学氧化处理.以该电化学氧化处理的碳纳米管(CV-CNT)纸为基体,采用电化学聚合沉积聚苯胺(PANI),随后吸附石墨烯(GR),制备具有三明治夹心结构的碳纳米管/聚苯胺/石墨烯(CV-CNT/PANI/GR)复合纳米碳纸.该结构外层为GR,内层由PANI包裹的CNT形成网络骨架,充分发挥三者各自优势构建柔性电极材料.用场发射扫描电镜(FE-SEM)、透射电子显微镜(TEM)、拉曼光谱对其形貌与结构进行表征,并测试其电化学性能.研究发现:PANI呈纳米晶须状,并均匀包裹在CV-CNT表面;该复合碳纸具有良好的电容特性、大电流充放电特性以及良好的循环稳定性能.电流密度为0.5A·g-1时,比电容可达415F·g-1;20A·g-1时仍能保持106F·g-1的比电容.由于GR的保护作用,1000次循环之后较CV-CNT/PANI保持更高的有效比电容.该CV-CNT/PANI/GR复合碳纸展现出在高性能超级电容器柔性电极材料的潜在应用价值.     

基于聚多巴胺的氮掺杂碳材料的制备及其电化学性能

多孔碳材料由于高的比表面积、优异的电子传导率、良好的化学稳定性等优点在超级电容器电极材料领域被广泛研究。 碳材料的组成及表面孔结构直接影响其电化学性能,为进一步提高碳材料的电容性能,本文首次以聚多巴胺球为前体,KOH为活化剂,通过高温碳化成功制备了良好电化学性能的氮掺杂多孔碳材料。 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、 X射线粉末衍射(XRD)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)和Raman光谱等对所制备的氮掺杂多孔碳材料进行了形貌及结构组成的表征。 在6 mol/L KOH电解液中, 采用循环伏安、恒电流充放电对多孔碳材料的电化学性能进行了研究。 结果表明,由于双电层电容和赝电容的协同作用,在电流密度为1 A/g时,材料的比电容可达269 F/g,充放电循环1000圈后电容仍可保留初始值的93.5%。     

自支撑三维功能化石墨烯/聚苯胺电极材料的制备及超级电容性能

采用水热法制备了三维石墨烯(3D-G),并以十八胺(ODA)为接枝剂对部分还原的氧化石墨烯进行氨基化处理,再利用原位聚合法在氨基化石墨烯表面生长聚苯胺,制备了十八胺功能化石墨烯/聚苯胺(G-ODA/PANI).对材料进行了结构表征、电化学性能分析和材料结构的比电容贡献分析.结果显示,电极材料的电容贡献大部分体现为材料的表面电容,G-ODA/PANI电极片在1 A/g电流密度时的比电容最高可达1080 F/g,是未功能化石墨烯/聚苯胺电极材料(G/PANI)的2.57倍,且循环稳定性也有很大的提高,循环10000周后的比容量保持率为90.8%,比G/PANI高9.6%.     

Al3+离子掺杂δ-MnO2的制备和电化学性能

采用水热法合成了不同比例Al³⁺离子掺杂的δ-MnO₂纳米粉体.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、 X射线光电子能谱(XPS)、循环伏安(CV)曲线、电化学阻抗谱(EIS)和恒电流充放电(GCD)曲线等手段对材料的结构和电化学性能进行了表征.结果表明, Al³⁺离子进入δ-MnO₂的晶格替代部分Mn³⁺和Mn⁴⁺离子,使得δ-MnO₂电极的性能明显提升.当反应物中Al³⁺/Mn²⁺摩尔比为0.45时,所得样品(A0.45M)的性能最好;其在1 A/g电流密度下的比电容为207.61 F/g,是纯相δ-MnO₂(A0M)的2.4倍;其在10 A/g电流密度下循环10000次后的比电容为100.81 F/g,容量保持率为81.33%.     

静电纺氧化锰复合碳纳米纤维柔性膜的电化学性能

采用一步法静电纺丝技术制备了具有超亲水特性的氧化锰/碳纳米纤维(MnO_x/CNFs)复合柔性膜电极材料,并通过X射线衍射、扫描电子显微镜和透射电子显微镜等对复合材料进行了表征.电化学性能测试结果表明,复合材料的电容性能优于单一材料,醋酸锰质量分数为40%时制得的复合纳米纤维电极(MC-4)在1 A/g电流密度下,于2 mol/L KOH电解液中的比电容高达1112.5 F/g,10 A/g电流密度下循环3000次比容量保持在93.4%,具有很好的稳定性.MnO_x/CNFs复合材料电化学性能增强一方面是由于三维超亲水纤维膜结构有利于电解液的快速浸润渗透,从而极大缩短了传输到材料基质的有效路径;另一方面是由于碳和MnO_x的协同效应,包裹在MnO_x粒子周围的碳层避免了MnO_x在充放电过程中的体积膨胀效应,这2种叠加机制促进了电化学性能的提升.     

自支撑石墨烯/聚苯胺纳米纤维薄膜的制备及其电化学电容行为

用真空抽滤氧化石墨（GO）与聚苯胺（PANI）纳米纤维的混合分散溶液,流动组装得到自支撑GO/PANI复合薄膜,再利用气态水合肼还原其中的GO,最后重新氧化和掺杂还原态PANI,制备了自支撑石墨烯（GN）/PANI薄膜.扫描电子显微镜（SEM）结果显示,GN/PANI薄膜为层状结构,且PANI纳米纤维均匀插层于GN片间.PANI纳米纤维在复合薄膜中的存在有效增大了GN之间的层间距,有利于电解液离也GN充分接触.GN的高电导性则有利于PANI氧化还原过程中的电荷传输.电化学测试表明,GN/PANI薄膜在1 mol·L^-1HCl电解液中具有良好的电化学电容性能,在0.1 A·g^-1的电流密度下的比容量为495 F·g^-1,在3A·g^-1时为313 F·g^-1.经过2000次连续充放电,其具有90%的电容保持率,表明该复合材料具有良好的电化学稳定性.     

褐煤基多孔炭/CoNi_2S_4复合材料的制备及电容特性研究

以宝清褐煤为原料,使用KOH溶液萃取、活化后制得煤基多孔炭,并利用简单的水热法将褐煤基多孔碳与CoNi_2S_4复合,制备复合电容电极材料。考察了不同碳添加量对褐煤基多孔碳/CoNi_2S_4复合材料电化学性能的影响,结果表明,碳添加量过高或过低都不利于复合材料比电容的提升,而碳添加量为37%的褐煤基多孔碳/CoNi_2S_4复合材料具有较高的比电容和良好的循环性能,该复合电极在4 A/g电流密度下,比电容达到1318.2 F/g,在4000次充放电循环后电容保持率为80.9%。     

双离子液体基多孔炭的制备与电化学性能

以质子型离子液体1-氢-3-乙烯基咪唑硫酸氢盐(HVImHSO₄)为主炭源, 以1-丁基-3-甲基咪唑六氟磷酸盐(BMImPF₆)为助剂, 在氮气气氛、 1000 ℃下一步炭化得到氮、 磷、 硫共掺杂多孔炭. 通过N₂吸附-脱附、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 X射线衍射(XRD)、 拉曼光谱(Raman)、 热重分析(TGA)和X射线光电子能谱(XPS)等技术对多孔炭进行了分析表征. 结果表明, 多孔炭的孔结构以微孔为主, 最高比表面积可达1111 m²/g, 其微晶结构中无定形碳和石墨化碳并存; 多孔炭中的氮主要以季氮(N-Q)、 吡咯氮(N-5)和吡啶氮(N-6)的形式存在, 磷以磷-氧(N—O—P)键合形式为主, 硫主要以噻吩硫(C—S—C)为主. 在6 mol/L KOH溶液、 三电极体系中, 多孔炭在0.5 A/g电流密度下的比电容为138 F/g; 在10 A/g电流密度下的比电容为100 F/g; 在2 A/g电流密度下循环充放电10000次, 其比电容保持率为95.8%, 显示出良好的电化学性能.     

N-CNTs/NiCo-LDH复合材料的制备及电化学性能

通过高温碳化聚吡咯纳米管制备了氮掺杂碳纳米管(N-CNTs), 并采用共沉淀法将镍钴层状双氢氧化物(NiCo-LDH)原位生长在N-CNTs上, 制备出具有三维互联网状结构的N-CNTs/NiCo-LDH复合材料. 研究了镍钴摩尔比对N-CNTs/NiCo-LDH复合材料形貌结构和电化学性能的影响. 结果表明, 当镍钴摩尔比为1∶2时, N-CNTs/Ni₁Co₂-LDH具有最佳的电化学性能. 在1 A/g电流密度下, 其比电容可达1311.8 F/g; 当电流密度为 10 A/g时, 电容保持率高达88.3%, 展现出优异的倍率性; 在经过2500次循环后, 电容保持率仍可达76.4%, 具有良好的循环稳定性.由N-CNTs/Ni₁Co₂-LDH与活性炭(AC)电极所构建的N-CNTs/Ni₁Co₂-LDH//AC水系混合型超级电容器, 在750 W/kg功率密度下, 具有27.19 W·h/kg的高能量密度.     

蒙脱土基氮掺杂多孔碳@聚苯胺复合材料的制备及电化学性能

分别在盐酸和樟脑磺酸-盐酸混酸溶液中,在蒙脱土基新型氮掺杂多孔碳表面原位聚合苯胺,以制备氮掺杂多孔碳@聚苯胺复合电极材料,采用红外光谱(FTIR)、X射线衍射(XRD)和扫描电子显微镜(SEM)表征复合材料的组成和形貌。 盐酸掺杂的复合材料呈短棒状形貌,樟脑磺酸-盐酸掺杂材料形貌呈颗粒状及交联片状,樟脑磺酸-盐酸掺杂的结晶性能优于盐酸掺杂。 电化学测试结果表明,樟脑磺酸-盐酸掺杂的复合材料在0.5 A/g电流密度下的质量比电容为412.5 F/g,比盐酸掺杂的(332.4 F/g)高24.1%,等效串联电阻(R_s)和电荷迁移电阻(R_ct)小;但盐酸掺杂的复合材料在大电流下电容保持率为81.4%,高于混酸掺杂的58.4%。     

Nitrogen-doped porous carbon coated on MnCo2O4 nanospheres as electrode materials for high-performance asymmetric supercapacitors

Spinel-based nanostructured materials are commonly used as promising electrode materials for supercapacitor applications. The combination of heteroatom-doped carbon material with spinel oxides substantially improves the specific capacitance and cyclic stability. In this work, dopamine-derived nitrogen-doped carbon was coated on spinel phase MnCo₂O₄ nanospheres using simple solvothermal and calcination methods. Surface morphology and the crystalline structure of the prepared MnCo₂O₄@Nitrogen-doped carbon were confirmed by FESEM and X-ray diffraction. The electrochemical performance of MnCo₂O₄@Nitrogen-doped carbon electrode material was analyzed by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. MnCo₂O₄@nitrogen-doped carbon exhibits the highest specific capacitance of 1200 F/g compared to MnCo₂O₄ spheres are 726 F/g at 1 A/g and exhibits excellent cyclic stability (capacitance retention of 87% at 7 A/g after 3000 cycles). The enhanced performance of the composite might be benefitted from the synergistic effect between nitrogen-doped carbon on porous MnCo₂O₄ spheres. Furthermore, an asymmetric supercapacitor device was fabricated by using the optimized composition of MnCo₂O₄@NC-2 as a positive electrode and nitrogen, sulfur-doped reduced graphene oxide (NS-rGO) as a negative electrode, respectively. This asymmetric supercapacitor device achieves a maximum energy density of 61.0 Wh/kg at a power density of 2889 W/kg and possesses excellent capacitance retention of 95% after 5000 cycles at 7 A/g.     

Boosting Supercapacitor Performance of Graphene by Coupling with Nitrogen-Doped Hollow Carbon Frameworks

Graphene as a suitable electrode has been extensively used for electrochemical double-layer capacitors based on its excellent properties, including high electrical conductivity and large specific surface area. However, one of the drawbacks is the unavoidable stacking tendency between the graphene nanosheets, resulting in limited electrochemically specific surface area. Herein, novel graphene nanosheets supported by hollow nitrogen-doped carbon frameworks derived from ZIF-8 (GPNC) were fabricated through a simple polyethyleneimine (PEI)-assisted pyrolysis strategy, to boost capacitance performance. Benefiting from the unique scaffold/support role of hollow nitrogen-doped carbon frameworks within the graphene interlayer, the GPNC with a large specific surface area, along with ample micropore/mesopore channels and high nitrogen content, is capable of facilitating electron and electrolyte ion migration kinetics and enhancing intrinsic electrochemical activity. Thus, the GPNC exhibits the highest charge storage of 218 F g⁻¹ and superior rate capability of 74 % when the current density increased from 0.5 to 20 Ag⁻¹ in comparison to pristine graphene and common ZIF-derived carbon/graphene electrodes. The assembled GPNC//GPNC two-electrode system further delivers a maximum power of 9080 Wkg⁻¹ with outstanding electrochemical retention of 84 % over 10 000 cycles.     

萘基相互连接的多孔碳纳米囊的制备及超电容性能

以萘为碳源, 采用MgO模板诱导耦合KOH裁剪技术制备了相互连接的多孔碳纳米囊(ICNC). 结果表明所制备的ICNC₂具有大的比表面积(1811 m²/g)、 高的压实密度(1.38 g/cm³)和微孔孔容含量(58.93%). 在对称的超级电容器(SC)中, ICNC₂电极的体积比容在不同电流密度下分别高达420.8 F/cm³(0.069 A/cm³)和315 F/cm³(27.6 A/cm³), 容量保持率为74.82%. 在38 W/L功率密度下, ICNC₂基SC的体积能量密度为14.6 W?h/L. 经过20000次循环后, 其体积比容仅衰减1.4%, 库伦效率为99.1%, 为从萘基小分子制备储能用功能碳材料提供了一种可行的方法.     

Effect of removing silica in rice husk for the preparation of activated carbon for supercapacitor applications

The significant influence of silica inside rice husk in the preparation and electrochemical performances of activated carbon are investigated. The removing of silica results in high mesoporous ratio and good rate capability.     

超级电容器用含氮碳与含氮碳/炭气凝胶复合电极材料的制备和性能研究

采用原位聚合法合成聚苯胺(PAIN)及聚苯胺/炭气凝胶(PAIN/CA)复合材料,经过高温裂解制备含氮碳(NC)及含氮碳/炭气凝胶复合材料(NC/CA),再以KOH为活化剂对其进行活化,制备活化含氮碳(ANC)及活化含氮碳/炭气凝胶复合材料(ANC/CA)。采用扫描电镜、循环伏安、恒流充放电以及电化学阻抗等方法进行性能测试,结果表明,由于KOH的活化作用,含氮碳材料的粒径明显变小,其比电容值为138 F/g,高于未活化含氮碳材料(98 F/g),ANC/AC3复合材料电极的比电容值比ACA电极(88 F/g)高,达到127 F/g。     

Peony pollen derived nitrogen-doped activated carbon for supercapacitor application

Peony pollen is a cheap and readily available biomass material with a relatively high protein content.In this work,it was employed as an N-rich precursor to prepare the nitrogen-doped porous carbon for supercapacitor application.The porous carbon microspheres were prepared through a hydrothermal method and subsequent carbonization process.Notably,ammonium borofruoride and potassium hydroxide were employed respectively as an etchant and an activator to modify the porosity of the materials.The as prepared ANPPCs-700 has a super high BET specific surface area of 824.69 m~2/g.The microstructure,chemical state and electrochemical properties of the product were investigated in detail.The prepared nitrogen-doped carbon microspheres exhibits excellent specific capacity of 209 F/g at a current density of lA/g and remained 92.5% of the initial capacitance after 5000 deep cycles at 5 A/g.     

Ni–Al composite hydroxides fabricated by cation–anion double hydrolysis method for high-performance supercapacitor

Chemical doping of nickel hydroxide with other cations(e.g. Al~(3+)) is an efficient way to enhance its electrochemical capacitive performances. Herein, a simple cation–anion(Ni~(2+)and AlO_2) double hydrolysis method was developed toward the synthesis of nickel–aluminum(Ni–Al) composite hydroxides. The obtained composite hydroxides possesses a porous structure, large surface area(121 m~2/g) and homogeneous element distribution. The electrochemical test shows that the obtained composite hydroxides exhibits a superior supercapacitive performances(specific capacitance of 1670F/g and rate capability of 87% from 0.5 A/g to 20 A/g) to doping-free nickel hydroxide(specific capacitance of 1227 F/g and rate capability of 47% from 0.5 A/g to 20 A/g). Moreover, the galvanostatic charge/discharge test displays that after 2000 cycles at large current density of 10 A/g, the composite hydroxides achieves a high capacitance retention of 98%, indicative of an excellent electrochemical cycleability.     

Synthesis of MnO2/N-doped ultramicroporous carbon nanospheres for high-performance supercapacitor electrodes

We demonstrate a simple and highly efficient strategy to synthesize MnO₂/nitrogen-doped ultramicroporous carbon nanospheres (MnO₂/N-UCNs) for supercapacitor application. MnO₂/N-UCNs were fabricated via a template-free polymerization of resorcinol/formaldehyde on the surface of phloroglucinol/terephthalaldehyde colloids in the presence of hexamethylenetetramine, followed by carbonization and then a redox reaction between carbons and KMnO₄. As-prepared MnO₂/N-UCNs exhibits regular ultramicropores, high surface area, nitrogen heteroatom, and high content of MnO₂. A typical MnO₂/N-UCNs with 57 wt.% MnO₂ doping content (denoted as MnO₂(57%)/N-UCNs) makes the most use of the synergistic effect between carbons and metal oxides. MnO₂(57%)/N-UCNs as a supercapacitor electrode exhibits excellent electrochemical performance such as a high specific capacitance (401 F/g at 1.0 A/g) and excellent charge/discharge stability (86.3% of the initial capacitance after 10,000 cycles at 2.0 A/g) in 1.0 mol/L Na₂SO₄ electrolyte. The well-designed and high-performance MnO₂/N-UCNs highlight the great potential for advanced supercapacitor applications.