高性能锂-空气电池材料的研究

以锂为负极,空气为正极的锂-空气二次电池,由于其较高的理论能量密度(5 210 Wh.kg-1)而成为最具发展潜力的新型高能化学电源体系。通过近几年的研究和开发,人们对这一体系的了解不断深入。虽然对其电化学过程中的复杂反应机理尚没有完整系统的理论描述,但是在氧还原催化剂、空气电极材料及电解质材料等方面已开展了一些研究工作。本文综述了锂-空气电池的最新研究进展,对电池的正极材料、电解质和负极材料三个方面的研究进行了介绍,分析了该体系的缺陷及存在的问题,并展望了锂-空气电池的发展方向和前景。     

非水体系锂-空气电池研究进展

锂-空气电池是目前已知具有最高能量密度的二次电池,有望成为未来电动汽车的动力电源。由于其能量密度高、环境友好以及成本较低,成为广大科研工作者研究的热点,在过去二十年间与之有关的研究已经在反应机理、电极结构、催化剂及电解液等各方面都取得了很大进展,但受诸多因素限制,其实用化仍然任重道远。本文总结了近几年来非水体系锂-空气电池在反应机理、正极材料、催化剂、电解液以及锂负极等方面的最新研究进展,并在此基础上展望其未来的发展方向。     

锂空气电池研究述评

由于锂空气电池具有很高的理论能量密度因而引起了广泛关注和研究。本文较为全面地论述了各种电解质体系中的锂空气电池的进展,包括:有机体系、水体系、离子液体体系、有机-水双电解质体系和全固态体系的锂空气电池;详细阐述和归纳了它们的工作原理和最新研究现状。对最新提出的锂-空气-超级电容电池的原理和特点进行了较详细的论述。结合氧气在有机电解质中的电化学还原行为指出单一有机电解质锂空气电池存在的问题以及可能的解决办法;同时展示了这类电池中空气电极催化剂的发展现状。结合双电解质锂空气电池、固态电解质锂空气电池、锂-空气-超级电容电池的结构阐述了它们各自的优缺点。本文还展示了一些可望用于单一有机电解质锂空电池、有机-水双电解质体系锂空电池的新型碳材料。最后对锂空气电池的研究发展进行了总结与展望,提出新型电解液、催化剂以及改进锂空气电池构造将会成为今后的发展趋势。     

非水系锂空气电池催化剂

近年来,随着对高性能电池需求的加大,锂空气电池因其超高的理论能量密度成为了研究热点。虽然锂空气电池的发展已取得了一些突破性的进展,但离实际应用差距甚远,仍有很多问题和挑战需要解决。其中,氧电极反应动力学速度缓慢就是一个非常严重的问题。为了促进锂空气电池的发展和应用,国际学术界对改善氧电极动力学速度的催化剂开展了大量的研究工作。本文总结了近年来国内外关于锂空气电池氧电极催化材料的主要研究进展,并对其未来发展作了前景展望。     

非水系锂空气电池碳基正极材料

锂空气电池因其极高的理论能量密度和环境友好等优点,有望成为下一代车用动力电源体系。然而,目前锂空气电池尚存在许多的问题和挑战,就正极而言,空气电极活性低的问题已成为制约锂空气电池技术发展最为重要的问题,因此,开发高性能锂空气电池正极催化剂一直以来都是该领域的重要研究课题。碳基催化剂(正极材料)是目前最具吸引力的锂空气电池正极材料之一,近年来得到了广泛的关注和研究。本文总结和介绍了近年来国内外在多孔碳基材料、石墨烯基材料、掺杂碳材料等碳材料作为锂空气电池正极材料方面的进展,包括本课题组在非水系锂空气电池正极材料方面的研究工作,并对碳基正极材料的发展及其在锂空气电池中的应用前景做了展望。     

CoOOH用作阴极催化剂对非水性锂-氧气电池性能的影响

利用工艺简单,成本低廉的共沉淀法制得CoOOH,并用作非水性锂-氧气电池阴极催化剂。通过恒流充放电、线性伏安扫描（LSV）和电化学阻抗（EIS）测试研究了电极的电化学性能。结果表明：由于CoOOH能够明显提高氧气还原反应（ORR）的催化活性,与未使用CoOOH的电极相比较,使用CoOOH为催化剂的电极首次放电容量高达5 093 mAh·g^-1,提高了1.7倍。电池的充电过电压降低了约460 mV,充电可逆性得到增强,充放电可逆性提高,使得循环性能得到显著改善。     

CoOOH用作阴极催化剂对非水性锂-氧气电池性能的影响

利用工艺简单,成本低廉的共沉淀法制得CoOOH,并用作非水性锂-氧气电池阴极催化剂。通过恒流充放电、线性伏安扫描（LSV）和电化学阻抗（EIS）测试研究了电极的电化学性能。结果表明：由于CoOOH能够明显提高氧气还原反应（ORR）的催化活性,与未使用CoOOH的电极相比较,使用CoOOH为催化剂的电极首次放电容量高达5 093 mAh·g^-1,提高了1.7倍。电池的充电过电压降低了约460 mV,充电可逆性得到增强,充放电可逆性提高,使得循环性能得到显著改善。     

电动汽车的希望:锂空气电池

以高中化学电化学知识为基础,介绍一种学界预期将对电动汽车储能领域产生革命性影响的可逆电池-锂-空气电池的基础知识,涉及这种电池的基本结构、工作原理、电极反应、研究现状、发展前景等内容。     

锂空气电池空气电极LiCoO2电催化性能研究

自设计建立锂空气电池实验装置,研究以掺入LiCoO2作为电催化剂的空气正极的电化学性能及其放电前后催化剂结构的变化.循环伏安、XRD及充放电测试等表明,LiCoO2能够很大程度地改善空气电极的放电性能.尤其是在放电前,将掺有LiCoO2的空气正极充电至4.1 V,此时LiCoO2的Co元素呈现较高的价态（Co3＋/Co...     

非水溶剂Li-O2电池锂负极研究进展

The aprotic Li-O₂ battery has attracted considerable interest in recent years because of its high theoretical specific energy that is far greater than that achievable with state-of-the-art Li-ion technologies. To date, most Li-O₂ studies, based on a cell configuration with a Li metal anode, aprotic Li⁺ electrolyte and porous O₂ cathode, have focused on O₂ reactions at the cathode. However, these reactions might be complicated by the use of Li metal anode. This is because both the electrolyte and O₂ (from cathode) can react with the Li metal and some parasitic products could cross over to the cathode and interfere with the O₂ reactions occurring therein. In addition, the possibility of dendrite formation on the Li anode, during its multiple plating/stripping cycles, raises serious safety concerns that impede the realization of practical Li-O₂ cells. Therefore, solutions to these issues are urgently needed to achieve a reversible and safety Li anode. This review summarizes recent advances in this field and strategies for achieving high performance Li anode for use in aprotic Li-O₂ batteries. Topics include alternative counter/reference electrodes, electrolytes and additives, composite protection layers and separators, and advanced experimental techniques for studying the Li anode|electrolyte interface. Future developments in relation to Li anode for aprotic Li-O₂ batteries are also discussed.     

Status Quo on Graphene Electrode Catalysts for Improved Oxygen Reduction and Evolution Reactions in Li-Air Batteries

Reduced global warming is the goal of carbon neutrality. Therefore, batteries are considered to be the best alternatives to current fossil fuels and an icon of the emerging energy industry. Voltaic cells are one of the power sources more frequently employed than photovoltaic cells in vehicles, consumer electronics, energy storage systems, and medical equipment. The most adaptable voltaic cells are lithium-ion batteries, which have the potential to meet the eagerly anticipated demands of the power sector. Working to increase their power generating and storage capability is therefore a challenging area of scientific focus. Apart from typical Li-ion batteries, Li-Air (Li-O₂) batteries are expected to produce high theoretical power densities (3505 W h kg⁻¹), which are ten times greater than that of Li-ion batteries (387 W h kg⁻¹). On the other hand, there are many challenges to reaching their maximum power capacity. Due to the oxygen reduction reaction (ORR) and oxygen evolution reaction (OES), the cathode usually faces many problems. Designing robust structured catalytic electrode materials and optimizing the electrolytes to improve their ability is highly challenging. Graphene is a 2D material with a stable hexagonal carbon network with high surface area, electrical, thermal conductivity, and flexibility with excellent chemical stability that could be a robust electrode material for Li-O₂ batteries. In this review, we covered graphene-based Li-O₂ batteries along with their existing problems and updated advantages, with conclusions and future perspectives.     

有机电极材料在非水系金属镁二次电池中的研究进展

由于镁资源储量丰富、成本低廉, 且金属镁具有理论体积比容量高(3833 mAh/cm³), 沉积/溶解过程中不易形成枝晶等优点, 金属镁二次电池受到了研究者的广泛关注. 然而, Mg²⁺较大的极性导致其在多数锂离子电池正极材料中无法实现可逆脱嵌. 主流无机电极材料普遍存在只能在较小电流密度下循环、动力学缓慢、制备工艺复杂等问题. 相较而言, 有机电极材料具有理论比容量高、结构多样易调控、资源丰富、环境友好、受离子半径和电荷影响小等优点, 被认为是一种有潜力的电极材料. 综述了近年来用于非水系镁二次电池有机正极材料的研究进展, 讨论了不同类型有机正极材料的电荷存储机制及电化学性能, 并总结了其面临的挑战、解决策略以及未来的发展方向.     

Towards Reversible High-Voltage Multi-Electron Reactions in Alkali-Ion Batteries Using Vanadium Phosphate Positive Electrode Materials

Vanadium phosphate positive electrode materials attract great interest in the field of Alkali-ion (Li, Na and K-ion) batteries due to their ability to store several electrons per transition metal. These multi-electron reactions (from V²⁺ to V⁵⁺) combined with the high voltage of corresponding redox couples (e.g., 4.0 V vs. for V³⁺/V⁴⁺ in Na₃V₂(PO₄)₂F₃) could allow the achievement the 1 kWh/kg milestone at the positive electrode level in Alkali-ion batteries. However, a massive divergence in the voltage reported for the V³⁺/V⁴⁺ and V⁴⁺/V⁵⁺ redox couples as a function of crystal structure is noticed. Moreover, vanadium phosphates that operate at high V³⁺/V⁴⁺ voltages are usually unable to reversibly exchange several electrons in a narrow enough voltage range. Here, through the review of redox mechanisms and structural evolutions upon electrochemical operation of selected widely studied materials, we identify the crystallographic origin of this trend: the distribution of PO₄ groups around vanadium octahedra, that allows or prevents the formation of the vanadyl distortion (O^…V⁴⁺=O or O^…V⁵⁺=O). While the vanadyl entity massively lowers the voltage of the V³⁺/V⁴⁺ and V⁴⁺/V⁵⁺ couples, it considerably improves the reversibility of these redox reactions. Therefore, anionic substitutions, mainly O²⁻ by F⁻, have been identified as a strategy allowing for combining the beneficial effect of the vanadyl distortion on the reversibility with the high voltage of vanadium redox couples in fluorine rich environments.     

锂-空气电池正极催化剂表界面调控及构效关系研究进展

锂-空气电池被认为是最具潜力的新一代化学电源体系之一,具有能量密度高、质量轻便、可逆性高、环境污染小等优点. 但其电极上缓慢的氧还原（ORR）与氧析出（OER）动力学过程导致了能量效率降低、过电位高、循环性能差等问题,制约了锂-空气电池的发展. 双效正极催化剂的设计与开发是解决上述问题的重要途径之一. 作者通过总结近几年锂-空气电池正极催化剂的研究进展,并结合其课题组自身的工作,综述了锂-空气电池正极催化剂表界面调控及构效关系研究方面的最新进展,并展望了未来关于锂-空气电池研究的切入点,对设计、开发高效锂-空电池催化剂具有重要指导意义.     

Electrochemical Evaluation of Diketopyrrolopyrrole Derivatives for Nonaqueous Redox Flow Batteries

Redox flow batteries (RFBs) employing nonaqueous electrolytes could potentially operate at much higher cell voltages, and therefore afford higher energy and power densities, than RFBs employing aqueous electrolytes. The development of such high-voltage nonaqueous RFBs requires anolytes that are electrochemically stable, especially in the presence of traces of oxygen and/or moisture. The inherent atmospheric reactivity of anolytes mandates judicious molecular design with high electron affinity and electrochemical stability. In this study, diketopyrrolopyrrole (DPP)-based TDPP-Hex-CN₄ is proposed as a stable redox-active molecule for anolytes in nonaqueous organic RFBs. We demonstrate organic RFBs using TDPP-Hex-CN₄ as anolyte with unisol blue (UB) 1,4-bis(isopropylamino)anthraquinone and 1,4-di-tert-butyl-2,5-bis(2-methoxyethoxy)benzene (DBBB) as catholytes. Cyclic voltammetry measurements with scans repeated over 200 cycles were performed to establish the electrochemical stability of the redox pairs. Symmetric flow-cell studies show that TDPP-Hex-CN₄ exhibits stable capacity up to 700 cycles. Redox flow cells employing TDPP-Hex-CN₄ /UB and TDPP-Hex-CN₄/DBBB as redox pairs demonstrate that DPP derivatives are propitious materials for anolytes in all organic nonaqueous RFBs.     

锂空气电池高容量长寿命Co3O4纳米空心球阴极催化剂

以六水合硝酸钴（Co(NO₃)₂·6H₂O）、六次甲基四胺（HMT）、蔗糖、柠檬酸钠（Na₃C₆H₅O₇）为原料,140 ^oC下水热碳化处理即得反应前驱物,经煅烧处理后,可得多孔Co₃O₄纳米空心球. 锂空气电池Co₃O₄/SP阴极催化剂具有优异的循环寿命性能,这归因于Co₃O₄空心球的纳米颗粒构成、较高比表面积的多孔结构,为电池反应提供了大量的反应位点,为充放电产物提供了足够的存储空间.     

Why Do Lithium–Oxygen Batteries Fail: Parasitic Chemical Reactions and Their Synergistic Effect

As an electrochemical energy‐storage technology with the highest theoretical capacity, lithium–oxygen batteries face critical challenges in terms of poor stabilities and low charge/discharge round‐trip efficiencies. It is generally recognized that these issues are connected to the parasitic chemical reactions at the anode, electrolyte, and cathode. While the detailed mechanisms of these reactions have been studied separately, the possible synergistic effects between these reactions remain poorly understood. To fill in the knowledge gap, this Minireview examines literature reports on the parasitic chemical reactions and finds the reactive oxygen species a key chemical mediator that participates in or facilitates nearly all parasitic chemical reactions. Given the ubiquitous presence of oxygen in all test cells, this finding is important. It offers new insights into how to stabilize various components of lithium–oxygen batteries for high‐performance operations and how to eventually materialize the full potentials of this promising technology.     

Reactions with Molecular Oxygen

Molecular oxygen is an important oxidizing agent both in industrial and in biological processes. In many of these processe, the O₂ molecule reacts preferentially with free radicals, which are frequently paramagnetic metal ions. Homogeneous systems of this type that are described in the literature are discussed, and an attempt is made to establish the factors that determine the course and mechanism of the reaction.     

钠离子电池电极材料研究进展

室温钠离子电池由于原料丰富,分布广泛,价格低廉,引起了人们的研究兴趣。然而,由于钠离子相对于锂离子较重且半径较大,这会限制钠离子在电极材料中的可逆脱嵌过程,从而影响电池的电化学性能。因此研发先进的电极材料成为钠离子电池实用化的关键。本文中我们主要介绍了几种典型的钠离子电池电极材料,并对其最新的研究进展进行了简要综述,将为钠离子电池新型电极材料的研究提供基础。     

锂离子电池有机硫化物电极材料*

有机硫化物电极材料是一类新型高比容量的储能材料,通过S-S键的可逆断裂与键合进行释能与储能,主要应用于锂离子电池的正极。该材料包括有机二硫化物、有机多硫化物和硫化聚合物等。本文综述了有机硫化物电极材料的研究现状,分析了各种材料的优势与不足,并展望了其发展趋势。如何提高现有材料的比容量并改善其循环性能是目前的研究重点。