水系钠离子电池电极材料研究进展

随着太阳能、风能等可再生能源发电并网普及应用和智能电网建设,储能技术成为能源优化利用的核心技术之一。水系钠离子电池具有资源丰富、价格低廉等优势,作为未来电网储能的重要选择而成为近年来电化学储能技术前沿的研究热点。由于受到水的热力学电化学窗口限制及嵌钠反应的特殊性(例如溶液的pH值、氧的溶解等),以及容量、电化学电位、适应性及催化效应等,电极材料选择面临挑战,进而影响水系钠离子电池的应用。因此,电极材料成为水系钠离子电池的研究重点。本文简要概括了水系钠离子电池的特点,并对氧化物、聚阴离子化合物、普鲁士蓝类似物和有机物等电极材料体系的最新研究进展进行了总结,并概括了将来的发展方向,为推动水系钠离子电池的发展和能源优化研究奠定了基础。     

氧化方式对发泡镍电极中CoOOH导电网络稳定性的影响

应用化学氧化(CO)和电化学氧化法(EO)于发泡式镍电极中引入CoOOH导电网络.循环伏安和X射线衍射法研究其还原氧化行为.实验表明,由化学氧化法制备的CoOOH(CO),其电化学还原氧化反应的可逆性优于CoOOH(EO);当镍电极的电位被强制性降低时,前者的结构能够保持稳定.因此,金属氢化物-镍电池经过强制性过放电储存后,于镍电极中引入CoOOH(CO)导电网络的电池容量保持率达到97.7%,而引入CoOOH(EO)导电网络的电池仅为81.4%.     

电化学转换反应及其在二次电池中的应用

电化学转换反应作为一种新的电极反应机制,近年来受到相当多的关注. 转换反应不仅能够利用金属化合物的多价态氧化还原,大幅度提高电化学容量利用率,而且对于主体晶格的结构、嵌脱阳离子的尺寸并无特殊要求,可以应用于众多不同种类的金属化合物,针对不同的金属离子设计高容量正负极活性材料. 因此,基于转换反应构建高容量电极材料正成为二次电池发展的一个新方向. 本文简要分析了电化学转换反应的基本原理和实现条件,并结合作者课题组近年来的研究工作探讨了这类反应在锂离子及钠离子电池中的潜在应用.     

Fe2O3/rGO纳米复合物的制备及其储锂和储钠性能

金属氧化物可通过电化学转换反应与锂离子及钠离子发生多电子可逆结构转换,是一类极具应用前景的高容量锂离子和钠离子电池负极材料。实验以氧化石墨烯和铁盐为前驱体,采用简单的溶剂法,成功将Fe₂O₃纳米单晶粒子均匀负载于石墨烯的导电片层上,获得Fe₂O₃/rGO(还原氧化石墨烯)纳米复合材料。复合电极在锂离子和钠离子电池中都表现出优异的充放电性能和循环稳定性。实验结果表明石墨烯的包覆不仅能降低Fe₂O₃发生转换反应的电荷传递阻抗,而且能够稳定电极在循环过程中带来的结构转变,极大改善电极大电流充放能力和循环稳定性。本研究为发展高容量的锂离子和钠离子电池负极材料提供了可行的途径。     

具有快速动力学特征的苯醌衍生物电极材料在水系质子电池中的设计和研究

含氧化还原活性基团的苯醌衍生物，在水系质子电池里是一种比容量高、资源丰富的理想电极材料，然而其高溶解性和低的工作电压不利于质子电池的循环稳定性和能量密度的提升，引入吸电子基团不仅可以降低其LUMO能量来提升其反应电位，还可以一定程度上抑制其溶解来提升稳定性。因此，通过电化学研究并对比了3种不同的苯醌化合物作为质子电池的电极材料，研究了不同氯取代情况造成的影响。其中四氯取代的四氯苯醌（4ClBQ）反应电位最高（0.51 V vs. Ag/AgCl），多电子氧化还原反应机制使其在水系质子电池里具有158 mAh/g的出色容量和高的倍率性能，并且氯取代有效抑制了溶解，在1 A/g的电流密度下也能稳定循环超过1200圈，显示出优异的性能。最后通过探究了电荷的快速反应动力学特征解释了出色的倍率性能。该研究表明，通过引入-Cl基团改进的4Cl-BQ，能进一步提升其在电池里综合性能，是一种极具发展潜力的水系质子电池材料。     

锑基钠离子电池负极材料的研究进展

钠离子电池由于具有能量密度高和钠资源丰富等优点而被认为是锂离子电池最有希望的替代品之一。合金型材料锑的理论容量高,氧化还原电位合适,是近年来钠离子电池负极材料的研究热点之一。本文主要介绍了锑单质、锑/碳复合材料、锑合金、锑的氧化物、锑的硫化物以及锑的其他复合物等锑基钠离子电池负极材料的研究现状。     

含异原子石墨炔基电极材料的研究进展

碳材料具有价格低廉、 易制备、 环境友好、 导电性高、 比表面积大以及适合离子存储和迁移等优点, 已成为目前应用于电化学储能器件电极的重要材料之一. 石墨炔(GDY)是一种新型的二维碳同素异形体, 由sp²碳杂化形式的苯环和sp碳杂化形式的炔键构成. 这种独特的化学结构一方面保持了碳材料良好的导电特性, 另一方面形成了新颖的离子传输通道, 为碳材料带来了不同的离子传输和存储特性. 与此同时, 由于石墨炔的空间结构可调性, 可以通过引入异原子微调石墨炔电子结构, 拓展石墨炔在电极材料领域的应用. 本文重点对近几年异原子杂化石墨炔基电极材料在锂离子电池、 钠离子电池、 金属硫电池、 电容器、 金属空气电池和电极保护等储能领域的研究工作进行总结, 并对未来石墨炔类材料在储能领域的发展进行了展望.     

基于有机物电极的电化学能量存储与转化

由于高安全的特性,水系二次电池被认为是未来大型储能的有效解决方案之一. 然而,现有水系电池主要以含金属元素的无机化合物为电极活性材料,其在大型储能中的实际应用仍受到循环寿命、环境问题、原料成本或金属元素丰度的限制. 相较于无机电极材料,部分有机电极材料具有原料丰富、结构丰富、可持续及环境友好等优点. 此外,有机物材料分子内空间大,能够存储不同价态电荷,因此近年来被广泛关注. 本文综述了课题组近期在有机物电极方面的研究进展,内容聚焦含羰基有机物通过C=O/C-O-的可逆转化存储单价金属阳离子(Li⁺, Na⁺)、双价金属阳离子(Zn²⁺)、质子(H⁺)所涉及的电化学过程,及其在水系锂、钠离子电池、水系锌离子电池、质子电池以及分步电解水中的应用.     

全固态钠离子电池硫系化合物电解质

全固态钠离子电池具有资源丰富、安全性高等优势,作为未来大规模储能的重要选择而成为近年来先进二次电池前沿研究热点。钠离子硫系化合物电解质室温离子电导率高、弹性模量高、容易冷压成型,能增强电极/电解质界面接触、减小界面阻抗、缓冲电极材料在充放电过程中的应力/应变,是全固态钠离子电池的研究重点。本文对钠离子硫系化合物固态电解质的结构及性质进行了总结,讨论了硫系化合物电解质的本征特性、与电极的界面稳定性,并介绍了硫系化合物全固态钠离子电池的研究现状,最后分析了硫系化合物电解质面临的挑战及今后的发展方向。     

有机自由基电池

有机自由基电池(ORB)是利用稳定的有机自由基聚合物作为电极活性材料的一类新型可充电电池,具有快速充电速度和良好的循环稳定性。此外,有机自由基聚合物还可制成薄膜电池。ORB不含有毒的重金属,其充放电依赖于有机自由基如氮氧自由基的氧化和还原反应,不同于锂离子电池依靠锂离子的脱嵌和嵌入。ORB为环境友好型电池,可作为笔记本电脑、智能卡、传感器和无线电频率识别标签等设备的潜在电源。本文综述了ORB的构成、特征、充放电机理以及研究进展,分析了高性能有机自由基电池的开发动态,包括通过自由基聚合物的多阶充放电特点成倍增加电池的放电容量,通过电极材料的纳米掺杂提高电池的循环稳定性,并指出了高放电容量有机自由基聚合物的设计原理、ORB的发展趋势和潜在应用领域。     

Strategies towards Low‐Cost Dual‐Ion Batteries with High Performance

Rocking‐chair based lithium‐ion batteries (LIBs) have extensively applied to consumer electronics and electric vehicles (EVs) for solving the present worldwide issues of fossil fuel exhaustion and environmental pollution. However, due to the growing unprecedented demand of LIBs for commercialization in EVs and grid‐scale energy storage stations, and a shortage of lithium and cobalt, the increasing cost gives impetus to exploit low‐cost rechargeable battery systems. Dual‐ion batteries (DIBs), in which both cations and anions are involved in the electrochemical redox reaction, are one of the most promising candidates to meet the low‐cost requirements of commercial applications, because of their high working voltage, excellent safety, and environmental friendliness compared to conventional rocking‐chair based LIBs. However, DIB technologies are only at the stage of fundamental research and considerable effort is required to improve the energy density and cycle life further. We review the development history and current situation, and discuss the reaction kinetics involved in DIBs, including various anionic intercalation mechanism of cathodes, and the reactions at the anodes including intercalation and alloying to explore promising strategies towards low‐cost DIBs with high performance.     

From Solid‐Solution Electrodes and the Rocking‐Chair Concept to Today's Batteries

Lithium‐ion batteries (LIBs) have become ubiquitous power sources for small electronic devices, electric vehicles, and stationary energy storage systems. Despite the success of LIBs which is acknowledged by their increasing commodity market, the historical evolution of the chemistry behind the LIB technologies is laden with obstacles and yet to be unambiguously documented. This Viewpoint outlines chronologically the most essential findings related to today's LIBs, including commercial electrode and electrolyte materials, but furthermore also depicts how the today popular and widely emerging solid‐state batteries were instrumental at very early stages in the development of LIBs.     

2D Materials as Ionic Sieves for Inhibiting the Shuttle Effect in Batteries

Alternatives of commercial lithium‐ion batteries (LIBs) have drawn huge attention due to the large demand of energy storage systems and the lack of resources for traditional LIBs. Promising candidates include but are not limited to Li‐S batteries, organic batteries and flow batteries. However, the dissolution of active materials and the consequent shuttle effect, as one of the main challenges in these candidates, always leads to significant capacity loss and poor cycling life. The rising two‐dimensional (2D) materials, with well‐defined structures and attractive physical and chemical properties, provide a new vision to solve these problems via suppressing the shuttle of the dissolved active materials. Herein, we present a minireview on the advances and perspectives of 2D materials as ionic sieves for inhibiting the shuttle effect in batteries.     

Metal-organic frameworks and their derivatives for Li-air batteries

Metal-organic frameworks(MOFs)are a class of outstanding materials in Li-air batteries because of their high surface areas,tailorable pore sizes and diverse catalytic centers.However,MOF-based batteries are facing challenges such as poor electronic conductivity and inferior long-cycle stability that limit their further development.This review first summarizes the progress of pristine MOFs and MOF-derived materials in Li-air batteries in the past 5 years,then provides a perspective for subsequent development of MOFs and their derivatives in this emerging field.     

Nitrogen Doped Carbon Coated Bi Microspheres as High-performance Anode for Half and Full Sodium Ion Batteries

As two-dimensional (2D) materials, bismuth (Bi) has large interlayer spacing along c-axis (0.395 nm) which provides rich active sites for sodium ions, thus guaranteeing high sodium ion storage activity. However, its poor electrical conductivity, combined with its degraded cycling performance, restricts its practical application. Herein, Bi microsphere coated with nitrogen-doped carbon (Bi@NC) was synthesized. Owing to the unique Bi crystals and nitrogen-doped carbon layer, the obtained Bi@NC anode exhibited satisfactory cycling stability and superior rate capability. Moreover, after assembling Bi@NC anode with Na₃V₂(PO₄)₃@C cathode to full battery, excellent sodium storage performance was obtained (57 mA h g⁻¹ after 2000 cycles at 1.0 A g⁻¹).     

VOCl as a Cathode for Rechargeable Chloride Ion Batteries

A novel room temperature rechargeable battery with VOCl cathode, lithium anode, and chloride ion transporting liquid electrolyte is described. The cell is based on the reversible transfer of chloride ions between the two electrodes. The VOCl cathode delivered an initial discharge capacity of 189 mAh g^?1. A reversible capacity of 113 mAh g^?1 was retained even after 100 cycles when cycled at a high current density of 522 mA g^?1. Such high cycling stability was achieved in chloride ion batteries for the first time, demonstrating the practicality of the system beyond a proof of concept model. The electrochemical reaction mechanism of the VOCl electrode in the chloride ion cell was investigated in detail by ex situ X‐ray diffraction (XRD), infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy (XPS). The results confirm reversible deintercalation–intercalation of chloride ions in the VOCl electrode.     

From Lithium‐Ion to Sodium‐Ion Batteries: Advantages,Challenges, and Surprises

Mobile and stationary energy storage by rechargeable batteries is a topic of broad societal and economical relevance. Lithium‐ion battery (LIB) technology is at the forefront of the development, but a massively growing market will likely put severe pressure on resources and supply chains. Recently, sodium‐ion batteries (SIBs) have been reconsidered with the aim of providing a lower‐cost alternative that is less susceptible to resource and supply risks. On paper, the replacement of lithium by sodium in a battery seems straightforward at first, but unpredictable surprises are often found in practice. What happens when replacing lithium by sodium in electrode reactions? This review provides a state‐of‐the art overview on the redox behavior of materials when used as electrodes in lithium‐ion and sodium‐ion batteries, respectively. Advantages and challenges related to the use of sodium instead of lithium are discussed.     

Progress of Organic Electrodes in Aqueous Electrolyte for Energy Storage and Conversion

Aqueous batteries using inorganic compounds as electrode materials are considered a promising solution for grid-scale energy storage, while wide application is limited by the short life and/or high cost of electrodes. Organics with carbonyl groups are being investigated as the alternative to inorganic electrode materials because they offer the advantages of tunable structures, renewability, and they are environmentally benign. Furthermore, the wide internal space of such organic materials enables flexible storage of various charged ions (for example, H⁺, Li⁺, Na⁺, K⁺, Zn²⁺, Mg²⁺, and Ca²⁺, and so on). We offer a comprehensive overview of the progress of organics containing carbonyls for energy storage and conversion in aqueous electrolytes, including applications in aqueous batteries as solid-state electrodes, in flow batteries as soluble redox species, and in water electrolysis as redox buffer electrodes. The advantages of organic electrodes are summarized, with a discussion of the challenges remaining for their practical application.     

Recent progress in the application of in situ atomic force microscopy for rechargeable batteries

High energy density batteries are urgently required for sustainable life. The intrinsic understanding of the reaction mechanism at the interfaces is essential for the progress. In this short overview, recent advances in rechargeable batteries by in situ atomic force microscopy are summarized, providing nanoscale information on the solid product evolution and metal plating/stripping inside working batteries. Besides, the multifunctional imaging of the morphology along with mechanical and electrical properties can be achieved to assist further interfacial design. Extensive applications of in situ atomic force microscopy are encouraged to explore the electrochemical mechanism and advanced engineering.