寻找高活性、低成本和耐用的析氧反应(OER)催化剂仍然是开发金属空气电池阴极的挑战。在此,我们提出了一种新的钴酸锰双金属自支撑电极作催化剂,采用水热和煅烧方法在碳布上合成钴酸锰双金属自支撑电极。该电极无需粘结剂和涂覆,可直接...寻找高活性、低成本和耐用的析氧反应(OER)催化剂仍然是开发金属空气电池阴极的挑战。在此,我们提出了一种新的钴酸锰双金属自支撑电极作催化剂,采用水热和煅烧方法在碳布上合成钴酸锰双金属自支撑电极。该电极无需粘结剂和涂覆,可直接作锌–空气电池阴极。以碳布(CC)为基底使用氮掺杂碳原位构筑钴酸锰,能增加碳表面的孔,暴露更多电化学活性位点。在碱性体系中对OER性能进行研究,结果显示催化剂在电流密度为10 mA·cm−2下具有203 mV的过电位,优于对比样品MnO2@NC/CC和Co3O4@NC/CC。此外,MnCo2O4.5@NC/CC材料所组装的锌空气电池具有优异的循环稳定性,在5 mA·cm−2电流密度下可以稳定循环200 h而电位无明显衰减。Exploring highly active, low-cost and durable catalysts for the oxygen precipitation reaction (OER) remains a challenge in developing cathodes for metal-air batteries. Herein, we present a new manganese cobaltate bimetallic self-supported electrode as a catalyst, which was synthesized on carbon cloth using hydrothermal and calcination methods. The electrode can be directly used as a zinc-air battery cathode without binder and coating. The in situ construction of manganese cobaltate using nitrogen-doped carbon on carbon cloth (CC) can increase the pores on the carbon surface and expose more electrochemically active sites. The OER performance was investigated in the alkaline system, and the results showed that the catalyst had an overpotential of 203 mV at a current density of 10 mA·cm−2, which was superior to the comparison samples, MnO2@NC/CC and Co3O4@NC/CC. In addition, the zinc-air battery assembled with MnCo2O4.5@NC/CC material has excellent cycling stability and can be stably cycled for 200 h at a current density of 5 mA·cm−2 without significant potential decay.展开更多
二维层状Ti3C2Tx因其独特的二维结构、金属导电性、丰富的化学表面、负的工作电势窗口,被认为非常具有应用前景的超级电容器负极材料。然而,二维纳米片层不可避免的堆叠导致其活性表面无法充分利用,限制其电化学性能。本文界面工程调控T...二维层状Ti3C2Tx因其独特的二维结构、金属导电性、丰富的化学表面、负的工作电势窗口,被认为非常具有应用前景的超级电容器负极材料。然而,二维纳米片层不可避免的堆叠导致其活性表面无法充分利用,限制其电化学性能。本文界面工程调控Ti3C2Tx表面,提高其活性表面利用率,提高其电荷存储能力。首先采用碱性溶液KOH预处理Ti3C2Tx,定向减少表面-F官能团,得到K+嵌入到Ti3C2Tx;再通过离子交换,实现过渡金属Mn2+离子插层,成功制备Mn2+修饰的Ti3C2Tx材料(Mn2+-Ti3C2Tx)。由于所制备Mn2+-Ti3C2Tx纳米片表面的Mn原子d轨道对周围-O官能团有很强的施主效应,对电解质离子有更强的吸附作用,能够促进电解质离子的输运,促进电化学反应在表面上进行,使得Mn2+-Ti3C2Tx电极材料在电流密度为1 A g−1时展现出323F g−1的高比容量。并且,在电流密度为20 A g−1时,电容保持率为83%。本文报道了一种高性能的Mn2+修饰的Ti3C2Tx材料,为超级电容器电极材料的开发提供了新的思路。Two-dimensional layered Ti3C2Tx is considered a very promising negative electrode material for supercapacitor applications due to its unique two-dimensional structure, metallic conductivity, abundant chemical surfaces, and negative working potential window. However, the unavoidable stacking of 2D nanosheets leads to the underutilization of its active surface, limiting its electrochemical performance. In this paper, interfacial engineering modulates the Ti3C2Tx surface to improve its active surface utilization and enhance its charge storage capacity. Firstly, Ti3C2Tx was pretreated with an alkaline solution of KOH to directionally reduce the -F surface functional groups, obtaining K+-embedded Ti3C2Tx. Subsequently, through ion exchange, the intercalation of Mn2+ transition metal ions was achieved, successfully fabricating Mn2+-modified Ti3C2Tx material (Mn2+-Ti3C2Tx). Owing to the strong donor effect of the d orbitals of Mn atoms on the surface of the prepared Mn2+-Ti3C2Tx nanosheets on the surrounding -O functional groups, there is a stronger adsorption of electrolyte ions, which promotes the transport of electrolyte ions and facilitates the electrochemical reaction on the surface, enabling the Mn2+-Ti3C2Tx electrode material to exhibit a high specific capacity of 323 F g−1 when the current density is 1 A g−1. Furthermore, when the current density is 20 A g−1, the capacitance retention rate is 83%. This paper reports a high-performance Mn2+-modified Ti3C2Tx material, offering a novel idea for the development of supercapacitor electrode materials.展开更多
本文通过利用基于钴金属有机骨架材料(ZIF-67)的高表面积和良好的结晶度作为前驱体,通过氮气气氛高温煅烧后形成C-ZIF-67材料,并通过原位聚合法,在C-ZIF-67材料表面生长密度均匀的聚苯胺(PANI)化合物,最终获得C-ZIF-67/PANI复合材料。采...本文通过利用基于钴金属有机骨架材料(ZIF-67)的高表面积和良好的结晶度作为前驱体,通过氮气气氛高温煅烧后形成C-ZIF-67材料,并通过原位聚合法,在C-ZIF-67材料表面生长密度均匀的聚苯胺(PANI)化合物,最终获得C-ZIF-67/PANI复合材料。采用CV、GCD和EIS电化学技术研究了C-ZIF-67/PANI复合电极在1 M硫酸电解液中的储能性能。最终表明,C-ZIF-67/PANI5复合电极可提供450.5 F g−1的比电容,并且在电流密度为8 A g−1下经过5000次的充放电循环测试后,比电容值仍保持初始比电容值的71%,表现其良好的循环稳定性。In this paper, the cobalt metal-organic framework material (ZIF-67) with high surface area and good crystallinity was used as the precursor. The C-ZIF-67 material was formed after calcination at high temperature under N2 atmosphere. Then, through the in-situ polymerization method, the polyaniline (PANI) compound with a uniform density was grown on the surface of the C-ZIF-67 material, and finally the C-ZIF-67/PANI composite material was obtained. The electrochemical techniques such as cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) were employed to investigate the energy storage performance of the C-ZIF-67/PANI composite electrode in 1 M sulfuric acid electrolyte. Eventually, it was demonstrated that the C-ZIF-67/PANI5 composite electrode could provide a specific capacitance of 450.5 F g⁻¹, and after 5000 charge-discharge cycling tests at a current density of 8 A g⁻¹, the specific capacitance value still remained 71% of the initial specific capacitance value, indicating its good cyclic stability.展开更多
文摘寻找高活性、低成本和耐用的析氧反应(OER)催化剂仍然是开发金属空气电池阴极的挑战。在此,我们提出了一种新的钴酸锰双金属自支撑电极作催化剂,采用水热和煅烧方法在碳布上合成钴酸锰双金属自支撑电极。该电极无需粘结剂和涂覆,可直接作锌–空气电池阴极。以碳布(CC)为基底使用氮掺杂碳原位构筑钴酸锰,能增加碳表面的孔,暴露更多电化学活性位点。在碱性体系中对OER性能进行研究,结果显示催化剂在电流密度为10 mA·cm−2下具有203 mV的过电位,优于对比样品MnO2@NC/CC和Co3O4@NC/CC。此外,MnCo2O4.5@NC/CC材料所组装的锌空气电池具有优异的循环稳定性,在5 mA·cm−2电流密度下可以稳定循环200 h而电位无明显衰减。Exploring highly active, low-cost and durable catalysts for the oxygen precipitation reaction (OER) remains a challenge in developing cathodes for metal-air batteries. Herein, we present a new manganese cobaltate bimetallic self-supported electrode as a catalyst, which was synthesized on carbon cloth using hydrothermal and calcination methods. The electrode can be directly used as a zinc-air battery cathode without binder and coating. The in situ construction of manganese cobaltate using nitrogen-doped carbon on carbon cloth (CC) can increase the pores on the carbon surface and expose more electrochemically active sites. The OER performance was investigated in the alkaline system, and the results showed that the catalyst had an overpotential of 203 mV at a current density of 10 mA·cm−2, which was superior to the comparison samples, MnO2@NC/CC and Co3O4@NC/CC. In addition, the zinc-air battery assembled with MnCo2O4.5@NC/CC material has excellent cycling stability and can be stably cycled for 200 h at a current density of 5 mA·cm−2 without significant potential decay.
文摘二维层状Ti3C2Tx因其独特的二维结构、金属导电性、丰富的化学表面、负的工作电势窗口,被认为非常具有应用前景的超级电容器负极材料。然而,二维纳米片层不可避免的堆叠导致其活性表面无法充分利用,限制其电化学性能。本文界面工程调控Ti3C2Tx表面,提高其活性表面利用率,提高其电荷存储能力。首先采用碱性溶液KOH预处理Ti3C2Tx,定向减少表面-F官能团,得到K+嵌入到Ti3C2Tx;再通过离子交换,实现过渡金属Mn2+离子插层,成功制备Mn2+修饰的Ti3C2Tx材料(Mn2+-Ti3C2Tx)。由于所制备Mn2+-Ti3C2Tx纳米片表面的Mn原子d轨道对周围-O官能团有很强的施主效应,对电解质离子有更强的吸附作用,能够促进电解质离子的输运,促进电化学反应在表面上进行,使得Mn2+-Ti3C2Tx电极材料在电流密度为1 A g−1时展现出323F g−1的高比容量。并且,在电流密度为20 A g−1时,电容保持率为83%。本文报道了一种高性能的Mn2+修饰的Ti3C2Tx材料,为超级电容器电极材料的开发提供了新的思路。Two-dimensional layered Ti3C2Tx is considered a very promising negative electrode material for supercapacitor applications due to its unique two-dimensional structure, metallic conductivity, abundant chemical surfaces, and negative working potential window. However, the unavoidable stacking of 2D nanosheets leads to the underutilization of its active surface, limiting its electrochemical performance. In this paper, interfacial engineering modulates the Ti3C2Tx surface to improve its active surface utilization and enhance its charge storage capacity. Firstly, Ti3C2Tx was pretreated with an alkaline solution of KOH to directionally reduce the -F surface functional groups, obtaining K+-embedded Ti3C2Tx. Subsequently, through ion exchange, the intercalation of Mn2+ transition metal ions was achieved, successfully fabricating Mn2+-modified Ti3C2Tx material (Mn2+-Ti3C2Tx). Owing to the strong donor effect of the d orbitals of Mn atoms on the surface of the prepared Mn2+-Ti3C2Tx nanosheets on the surrounding -O functional groups, there is a stronger adsorption of electrolyte ions, which promotes the transport of electrolyte ions and facilitates the electrochemical reaction on the surface, enabling the Mn2+-Ti3C2Tx electrode material to exhibit a high specific capacity of 323 F g−1 when the current density is 1 A g−1. Furthermore, when the current density is 20 A g−1, the capacitance retention rate is 83%. This paper reports a high-performance Mn2+-modified Ti3C2Tx material, offering a novel idea for the development of supercapacitor electrode materials.
文摘本文通过利用基于钴金属有机骨架材料(ZIF-67)的高表面积和良好的结晶度作为前驱体,通过氮气气氛高温煅烧后形成C-ZIF-67材料,并通过原位聚合法,在C-ZIF-67材料表面生长密度均匀的聚苯胺(PANI)化合物,最终获得C-ZIF-67/PANI复合材料。采用CV、GCD和EIS电化学技术研究了C-ZIF-67/PANI复合电极在1 M硫酸电解液中的储能性能。最终表明,C-ZIF-67/PANI5复合电极可提供450.5 F g−1的比电容,并且在电流密度为8 A g−1下经过5000次的充放电循环测试后,比电容值仍保持初始比电容值的71%,表现其良好的循环稳定性。In this paper, the cobalt metal-organic framework material (ZIF-67) with high surface area and good crystallinity was used as the precursor. The C-ZIF-67 material was formed after calcination at high temperature under N2 atmosphere. Then, through the in-situ polymerization method, the polyaniline (PANI) compound with a uniform density was grown on the surface of the C-ZIF-67 material, and finally the C-ZIF-67/PANI composite material was obtained. The electrochemical techniques such as cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) were employed to investigate the energy storage performance of the C-ZIF-67/PANI composite electrode in 1 M sulfuric acid electrolyte. Eventually, it was demonstrated that the C-ZIF-67/PANI5 composite electrode could provide a specific capacitance of 450.5 F g⁻¹, and after 5000 charge-discharge cycling tests at a current density of 8 A g⁻¹, the specific capacitance value still remained 71% of the initial specific capacitance value, indicating its good cyclic stability.
