新型超级电容器的研发进展

传统超级电容器受低能量密度的限制,在当今器件研发中需更加关注电极材料结构-组成-性能研究。 本文总结了新型赝电容器的发展历程及其研发过程中存在的挑战与解决措施,着重从胶体离子超级电容器电极材料等新型的电极材料和氧化还原电解质两个方面进行综述。 原位合成的胶体离子超级电容器电极材料比非原位合成的电极材料具有更高的反应活性,并且以近似离子的状态存在,有效增加了电极材料的比容量。 氧化还原电解质的使用在不改变电极材料的前提下,进一步提高了超级电容器的能量密度。 初步介绍了新型锂离子电容器。 锂离子电容器同时使用电池型材料和电容型材料,可提高其能量密度。 依据当前超级电容器的研发现状,未来有望将电池材料和电容器材料结合使用,进而形成电池电容器或电容电池,使其同时具有高的能量密度和功率密度。     

锂离子电池负极碳材料的表面改性与修饰Ⅰ．表面的氧化、还原处理对碳材料电极性能的影响

通过各种氧化／还原体系对碳材料进行表面氧化、还原处理,研究了碳材料表面的痕量有机含氧官能团对以碳材料作为锂离子电池负极的电池性能的影响．结果表明,碳材料表面大量有机含氧官能团的存在将引起电池性能的严重恶化;相应地如对电极表面进行一定的还原处理、以减少碳表面有机官能团的含量及其氧化程度则可提高电极（碳材料）的容量及首次循环效率．文中还结合碳材料表面有机官能团对电解液溶剂的分解反应以及碳电极表面钝化膜形成的影响进行了解释．     

锂离子电池负极碳材料的表面改性与修饰：Ⅰ.表面的氧化,还原处理对碳…

通过各种氧化／还原体系对碳材料进行表面氧化，还原处理，研究了碳材料表面的痕量有机含氧官能团对以碳材料作为锂离子电池负极的电池性能的影响。结果表明，碳材料表面大量有机含氧官能团的存在将引起电池性能的严重恶化；相应地如对电极表面进行一定的还原处理，以减少碳表面有机官能团的含量及其氧化程度则可提高电极的容量及首次循环效率。     

氮掺杂还原氧化石墨烯负载铂催化剂的制备及甲醇电氧化性能

采用高温热解聚苯胺修饰的氧化石墨烯（PANI-GO）,得到了氮掺杂的还原氧化石墨烯碳材料（N-RGO）,以其负载Pt 制备了Pt/N-RGO纳米结构电催化剂. 采用透射电镜（TEM）、X射线光电子能谱（XPS）、X 射线衍射（XRD）谱及拉曼光谱等技术对N-RGO和Pt/N-RGO的形貌及结构进行了表征,用循环伏安、计时电流等电化学技术研究了Pt/N-RGO电极催化剂对CO溶出反应和甲醇电氧化反应的催化性能. 结果表明：高温热解PANIGO可同时实现GO的还原及其氮掺杂的过程,氮掺杂引起还原氧化石墨烯碳材料表面缺陷结构和导电性的增加;与相应的未掺杂氮样品Pt/RGO相比较,Pt/N-RGO样品上Pt 颗粒的分散更均匀,显示出更强的抗CO毒化能力和更高的甲醇电氧化催化活性及稳定性.     

电极电势和氧化还原反应

以实验为例讨论电极电势和氧化还原反应的关系,总结出如何通过电极电势差判断反应倾向;电极电势与氧化还原反应的速率无关;氧化还原反应和酸碱性的关系以及运用电极电势应关注的问题。     

氮掺杂还原氧化石墨烯负载铂催化剂的制备及甲醇电氧化性能

采用高温热解聚苯胺修饰的氧化石墨烯(PANI-GO),得到了氮掺杂的还原氧化石墨烯碳材料(N-RGO),以其负载Pt制备了Pt/N-RGO纳米结构电催化剂.采用透射电镜(TEM)、X射线光电子能谱(XPS)、X射线衍射(XRD)谱及拉曼光谱等技术对N-RGO和Pt/N-RGO的形貌及结构进行了表征,用循环伏安、计时电流等电化学技术研究了Pt/N-RGO电极催化剂对CO溶出反应和甲醇电氧化反应的催化性能.结果表明:高温热解PANIGO可同时实现GO的还原及其氮掺杂的过程,氮掺杂引起还原氧化石墨烯碳材料表面缺陷结构和导电性的增加;与相应的未掺杂氮样品Pt/RGO相比较,Pt/N-RGO样品上Pt颗粒的分散更均匀,显示出更强的抗CO毒化能力和更高的甲醇电氧化催化活性及稳定性.     

Ce^4^+/Ce^3^+-V^2^+/V^3^+氧化还原流动电池的可行性研究2: 旋转圆盘(RDE) 与旋转环盘(RRDE)法对Ce^4^+/Ce^3^+氧化还原体系的研究

用RDE与RRDE法研究了Ce^4^+/Ce^3^+-V^2^+/V^3^+氧化还原流动电池中Ce^4^+/Ce^3^+体系的电化学动力学参数,以说明组成该新型氧化流动电池的可能性。用RDE法得出在铂电极表面与玻碳电极上均会生成一层氧化膜,对Ce^3^+的氧化的反应产生阻碍作用。但在铂上的氧化膜对Ce^4^+的还原反应却有催化作用。用RRDE法得出Ce^3^+在玻碳电极上的氧化与析氧之间存在着竟争,为得到高的Ce^3^+氧化效率,应控制氧化电流在2～8mA.cm^-^2之间。     

Ce^4^+/Ce^3^+-V^2^+/V^3^+氧化还原流动电池的可行性研究2: 旋转圆盘(RDE) 与旋转环盘(RRDE)法对Ce^4^+/Ce^3^+氧化还原体系的研究

用RDE与RRDE法研究了Ce^4^+/Ce^3^+-V^2^+/V^3^+氧化还原流动电池中Ce^4^+/Ce^3^+体系的电化学动力学参数,以说明组成该新型氧化流动电池的可能性。用RDE法得出在铂电极表面与玻碳电极上均会生成一层氧化膜,对Ce^3^+的氧化的反应产生阻碍作用。但在铂上的氧化膜对Ce^4^+的还原反应却有催化作用。用RRDE法得出Ce^3^+在玻碳电极上的氧化与析氧之间存在着竟争,为得到高的Ce^3^+氧化效率,应控制氧化电流在2～8mA.cm^-^2之间。     

染料修饰电极加速氧化还原蛋白质的电化学反应

评述了染料修饰电极加速氧化还原蛋白质的电子传递反应。讨论了染料修饰电极的修饰方法和性质。简述了伏安法、流动分析、光谱电化学法等几种不同研究方法的应用。提出了可逆电催化反应的机理，并将数值计算与实验结果进行比较、验证。引用了４７篇文献。     

全钒氧化还原液流电池用石墨毡电极的分步氧化活化

石墨毡电极是组成钒电池的关键材料,其较低的电化学活性是造成钒电池功率密度较低的关键因素之一. 本论文采用一种简便的石墨毡电极分步氧化活化法,先将石墨毡在高锰酸钾溶液中进行氧化,后置于活化溶液中激发其反应活性. 通过对处理后的石墨毡进行循环伏安、交流阻抗测试、XPS以及SEM表征,发现氧化时间和活化溶液组成是影响电极性能的因素,在本文中,先经过3天氧化时间,后在配比为3:1的活化溶液中处理的电极,较其他方法处理的电极,电荷传递电阻明显降低,其与溶液之间的接触电阻最低,为7.33 Ω·cm ²,氧化还原峰值比更接近于1,有效提高了反应的活性与可逆性,经X射线光电子能谱分析发现性能提高的原因与表面含氧官能团数目增加有关. 单电池性能测试结果进一步证实,利用该方法处理的石墨毡为电极的单电池,较未经处理的电池相比性能更优,有更高的放电容量和能量效率,在100 mA·cm ^-2电流密度下,能量效率较未处理电极高出7.47%. 与热处理法、酸处理法及电化学氧化法相比较,该方法不需要辅助设备,不消耗能源.     

A Perspective on Studying Electronic Structure of Batteries through Soft X-ray Spectroscopy

Understanding electronic structure is crucial to enhance the battery performance. Soft X-ray spectroscopy(SXS) is one of the most effective methods to provide direct probe of electronic states. Here, spectroscopic measurements of transition metal 3 d and oxygen 2 p states are simply reviewed. Then, we mainly focus on the perspective of the development direction of modern SXS techniques. Although the true power of recently developed high efficiency mapping of resonant inelastic X-ray scattering(m RIXS) has been apparent for materials and chemistry studies, great challenges remain for mRIXS spectroscopic interpretation, and the understanding of the battery materials on novel redox activities remains elusive.     

Redox Reaction in Ti−Mn Redox Flow Battery Studied by X-ray Absorption Spectroscopy

We performed X-ray absorption studies for the electrolytes of a Ti−Mn redox flow battery (RFB) to understand the redox reaction of the Ti/Mn ions and formation of precipitates in charged catholyte, because suppression of the disproportionation reaction is a key to improve the cyclability of Ti−Mn RFB and enhance the energy density. Hard X-ray absorption spectroscopy with a high transmittance and soft X-ray absorption spectroscopy to directly observe the 3d orbitals were complementarily employed. Moreover, the Ti/Mn 3d electronic structure for each precipitate and solution in the charged catholyte was investigated by using scanning transmission X-ray microscopy: the valence of Mn in the precipitate is mostly attributed to 4+, and the solution includes only Mn²⁺. This charge disproportionation reaction should occur after the Mn ions in the catholyte should be oxidized from Mn²⁺ to Mn³⁺ by charge.     

Rational material design of Li-excess metal oxides with disordered rock salt structure

This review article summarizes recent research development on a new class of electrode materials with a cation-disordered rock salt structure for energy storage applications. Historically, oxide-based electrode materials with the disordered rock salt structure are regarded as “electrochemically inactive.” However, recent experimental and theoretical research reveals that many oxides with the disordered rock salt structure can be utilized as high-capacity electrode materials, which deliver a much larger reversible capacity compared with traditional and cation ordered layered materials used for practical battery applications. For these emerging electrode materials, higher energy density is achieved relying on anionic and/or cationic redox as multi-electron reactions. Moreover, this anionic/cationic redox for Li-excess materials with the rock salt structure is effectively activated for nano-sized materials. These new trends for the material design on high-capacity electrode materials are highlighted and the future direction to design Li/Na insertion materials for energy storage applications is outlooked.     

阴离子硫氧化还原与Li1-xNiO2-ySy的结构稳定性:第一性原理研究

Ni-rich layered oxides are the preferred cathode materials for high-energy-density lithium-ion batteries currently used in electric vehicles. In this paper, we present a systematic first-principles evaluation of the deintercalation process in the Li_1-xNiO_2-yS_y. The partial density of states (PDOS) characters of the electrons near the Fermi level, redox behaviors, and thermal stability have been investigated within the GGA+U scheme. The results show that the introduction of sulfur alleviates the lattice distortion during charging, suppresses nickel migration, and enhances the stability of oxygen according to the contribution of sulfur anion redox to the charge compensation for the overcharged Li_1-xNiO_2-yS_y. This study provides a new insight on improving the stability of Ni-rich cathode materials by tuning of the electrochemical behaviors based on sulfur anion redox.     

离子的胶体状态与其电化学储能极限

阳离子氧化还原化学是电化学储能技术中最核心的储能机理,如何高效快速利用氧化还原活性阳离子是发展兼具高功率密度与高能量密度储电技术的关键。 处于胶体状态的阳离子可形成热力学平衡态和非平衡态,具有高反应活性和低离子迁移势垒,展现出独特的电化学特性。 本文着重介绍氧化还原活性阳离子的胶体状态与其在电化学储能上的应用,并从热力学和动力学方面阐述其储能机理,以及活性胶体离子电极和超级电容电池的构筑。 利用胶体的高比表面积、高离子吸附能力和荷电离子梯度分布等特性,创造性地构筑胶体超级电容电池,解决了现有电化学储能电极材料体系中高容量与高功率不能兼具的问题,同时开拓了胶体体系新的应用方向。     

Reversible Anionic Redox Activities in Conventional LiNi1/3Co1/3Mn1/3O2 Cathodes

Redox reactions of oxygen have been considered critical in controlling the electrochemical properties of lithium‐excessive layered‐oxide electrodes. However, conventional electrode materials without overlithiation remain the most practical. Typically, cationic redox reactions are believed to dominate the electrochemical processes in conventional electrodes. Herein, we show unambiguous evidence of reversible anionic redox reactions in LiNi_1/3Co_1/3Mn_1/3O₂. The typical involvement of oxygen through hybridization with transition metals is discussed, as well as the intrinsic oxygen redox process at high potentials, which is 75 % reversible during initial cycling and 63 % retained after 10 cycles. Our results clarify the reaction mechanism at high potentials in conventional layered electrodes involving both cationic and anionic reactions and indicate the potential of utilizing reversible oxygen redox reactions in conventional layered oxides for high‐capacity lithium‐ion batteries.     

液流电池研究进展

和通常熟悉的以固体或气体材料作电极的化学电源不同,液流电池的活性物质是流动着的电解质溶液,是一种可实现规模化储能的电化学装置.本文简要综述液流电池的发展历史及其研究现状,瞻望发展前景,并提出它存在的主要问题.     

Redox‐Triggered Reversible Interconversion of a Monocyclic and a Bicyclic Phosphorus Heterocycle

Molecules which change their structures significantly and reversibly upon an oxidation or reduction process have potential as future components of smart materials. A prerequisite for such an application is that the molecules should undergo the redox‐coupled transformation within a reasonable electrochemical window and lock into stable redox states. Sodium phosphaethynolate reacts with two equivalents of dicyclohexylcarbodiimide (DCC) to yield an anionic, imino‐functionalized 1,3,5‐diazaphosphinane [ 3 a ]^?. The oxidation of this anion with elemental iodine causes an intramolecular rearrangement reaction to give a bicyclic 1,3,2‐diazaphospholenium cation [ 6 ]⁺. This umpolung of electronic properties from non‐aromatic to highly aromatic is reversible, and the cation [ 6 ] ⁺ is reduced with elemental magnesium to reform the 1,3,5‐diazaphosphinanide anion [ 3 a ]^?. Theoretical calculations suggest that phosphinidene species are involved in the rearrangement processes.