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.     

Magnesium-Bismuth System: Thermodynamic Properties and Prospects for Use in Magnesium-Ion Batteries

Along with large-scale studies of promising electrode materials for lithium-ion and sodium-ion batteries, in the past 10–15 years there has been interest in rechargeable batteries with magnesium anode and in magnesium-ion batteries. Bismuth shows promise as a material for the negative electrode of magnesium-ion batteries. The review summarizes the data on the thermodynamic properties of magnesium-bismuth alloys and on possible use of bismuth or bismuth alloys in magnesium-ion batteries.

     

磷酸三甲酯和碳酸亚乙烯酯对锂离子电池的复合作用

应用循环伏安、交流阻抗、扫描电子显微镜和锂离子电池性能检测装置研究了阻燃添加剂磷酸三甲酯(TMP)和成膜添加剂碳酸亚乙烯酯(VC)对锂离子电池的复合作用.结果表明,复合使用TMP和VC不仅能提高电池的安全性而且能改善电池的循环性能,原因可能是在电池首次充放电过程中VC优先还原,还原产物在负极表面聚合形成良好的SEI膜,有效地制约了因TMP在石墨负极表面的分解而造成负极石墨的脱落,同时提高了SEI膜的稳定性.     

Power sources for portable electronics and hybrid cars: lithium batteries and fuel cells

The activities in progress in our laboratory for the development of batteries and fuel cells for portable electronics and hybrid car applications are reviewed and discussed. In the case of lithium batteries, the research has been mainly focused on the characterization of new electrode and electrolyte materials. Results related to disordered carbon anodes and improved, solvent-free, as well as gel-type, polymer electrolytes are particularly stressed. It is shown that the use of proper gel electrolytes, in combination with suitable electrode couples, allows the development of new types of safe, reliable, and low-cost lithium ion batteries which appear to be very promising power sources for hybrid vehicles. Some of the technologies proven to be successful in the lithium battery area are readapted for use in fuel cells. In particular, this approach has been followed for the preparation of low-cost and stable protonic membranes to be proposed as an alternative to the expensive, perfluorosulfonic membranes presently used in polymer electrolyte membrane fuel cells (PEMFCs).     

A short perspective of modeling electrode materials in lithium-ion batteries by the ab initio atomistic thermodynamics approach

Atomic-scale insights into the performance of electrode materials in lithium-ion batteries require thermodynamic considerations as first step in order to determine potential surface structures that are relevant for subsequent kinetic studies. Within the last 20 years, research in heterogeneous catalysis as well as in electrocatalysis has been spurred by the ab initio atomistic thermodynamics approach, whose application for electrode materials in lithium-ion batteries is eyed and discussed in this perspective article.     

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.     

Preliminary study of single flow zinc–nickel battery

A novel redox flow battery–single flow Zn/NiOOH battery is proposed. The electrolyte of this battery for both negative electrode and positive electrode is high concentration solutions of ZnO in aqueous KOH, the negative electrode is inert metal such as nickel foil, and the positive electrode is nickel oxide for secondary alkaline batteries. Typically, there is no requirement for a membrane in the battery. Ni(OH)₂ is oxidized to NiOOH at positive electrode and the zincate ions is reduced to zinc and electroplated onto the negative electrode during charge. The reverse occurs during discharge. Results obtained with a small laboratory cell show that high efficiencies can be achieved with an average coulombic efficiency of 96% and energy efficiency of 86% over 1000 cycles. High performance obtained indicates that the single flow zinc/nickel battery is a promising battery.     

Research of Nanomaterials as Electrodes for Electrochemical Energy Storage

This paper has experimentally proved that hydrogen accumulates in large quantities in metal-ceramic and pocket electrodes of alkaline batteries during their operation. Hydrogen accumulates in the electrodes in an atomic form. After the release of hydrogen from the electrodes, a powerful exothermic reaction of atomic hydrogen recombination with a large energy release occurs. This exothermic reaction is the cause of thermal runaway in alkaline batteries. For the KSL-15 battery, the gravimetric capacity of sintered nickel matrix of the oxide-nickel electrode, as hydrogen storage, is 20.2 wt%, and cadmium electrode is 11.5 wt%. The stored energy density in the metal-ceramic matrix of the oxide-nickel electrode of the battery KSL-15 is 44 kJ/g, and in the cadmium electrode it is 25 kJ/g. The similar values for the KPL-14 battery are as follows. The gravimetric capacity of the active substance of the pocket oxide-nickel electrode, as a hydrogen storage, is 22 wt%, and the cadmium electrode is 16.9 wt%. The density of the stored energy in the active substance oxide-nickel electrode is 48 kJ/g, and in the active substance of the cadmium electrode it is 36.8 kJ/g. The obtained results of the accumulation of hydrogen energy in the electrodes by the electrochemical method are three times higher than any previously obtained results using the traditional thermochemical method.     

Sodium Ion Batteries using Ionic Liquids as Electrolytes

Sodium ion batteries have been developed using ionic liquids as electrolytes. Sodium is superior to lithium as a raw material for mass production of large‐scale batteries for energy storage due to its abundance and even distribution across the earth. Ionic liquids are non‐volatile and non‐flammable, which improved the safety of the batteries remarkably. In addition, operation temperatures were extended to higher values, improving the performance of the batteries by facilitating the reaction at the electrode and mass transfer. Binary systems of sodium and quaternary ammonium salts, such as 1‐ethyl‐3‐methylimidazolium and N‐methyl‐N‐propylpyrrolidinium bis(fluorosulfonyl)amide, were employed as electrolytes for sodium ion batteries. A series of positive and negative electrode materials were examined to be combined with these ionic liquid electrolytes. A 27 Ah full cell was fabricated employing sodium chromite (NaCrO₂) and hard carbon as positive and negative electrode materials, respectively. The gravimetric energy density obtained for the battery was 75 Wh kg^?1 and its volumetric energy density was 125 Wh L^?1. The capacity retention after 500 cycles was 87 %. Further improvement of the cell performance and energy density is expected on development of suitable electrode materials and optimization of the cell design.     

Enhancing the performances of Li-ion batteries by carbon-coating: present and future

With progress of knowledge of electrode materials, it has been found that their surface structures are of great importance to the electrochemical performance of Li-ion batteries. Carbon coating can effectively increase the electrode conductivity, improve the surface chemistry of the active material, and protect the electrode from direct contact with electrolyte, leading to enhanced cycle life of the batteries. Carbon coating together with nanotechnology provides good conductivity as well as fast Li-ion diffusion, and thus also results in good rate capabilities. The recent development of carbon coating techniques in lithium-ion batteries is discussed with detailed examples of typical cathode and anode materials. The limitation of current technology and future perspective of the new concept of "hybrid coating" are also pointed out.     

Treated carbon felt as electrode material in vanadium redox flow batteries: a study of the use of carbon nanotubes as electrocatalyst

Electrodes for large-scale usage in vanadium redox flow battery are usually fabricated without any electrocatalyst due to the lack of good, viable options. The best performance is achieved of carbon-based materials. Recently, some researchers have been reported regarding the use of carbon nanotube as the electrocatalyst in the vanadium redox flow batteries. However, these researches have been carried out without making any comparison between the performance of the traditional method and the carbon nanotube electrocatalyst. In the present study, the loading of multi-walled carbon nanotube, the acid–heat treatment, and their combination were used to modify the carbon felt electrode to be applied in the vanadium redox flow battery. The obtained results showed better electrochemical properties for acid–heat-treated carbon felt electrode compared to the carbon nanotube-loaded one. The best electrode was obtained for using in a vanadium redox flow battery in terms of electrochemical and surface properties after applying a combination of two modification strategies. Applying this proposed method in modification of the carbon felt electrode increased its hydrophilicity more than 17 times and its capability to absorb VOSO₄ solution more than eight times. Also, the charge transfer resistance of a modified electrode, by the combination of the carbon nanotube and the acid–heat treatment, significantly decreased in both positive and negative poles of vanadium redox flow battery. Consequently, the exchange current density enhanced more than 100- and 175-fold in positive and negative poles, respectively, in comparison with carbon felt electrode.     

一种适于高速充电的新型化学电源电极的研究

本文提出一种适于高速充电的新型化学电源电极，该电极体系在充电时，反应界面能迅速推移，使活性物质能迅速沉积在三维载体电极上，特别适用于强电流高速充电。充电时活性物质以固态沉积在电极表面，而放电时活性物质又溶解为液态。电极体系在充放电循环过程中活性物质是以固（态）－液（态）循环形式进行循环，因而可以保持新鲜的电极表面，防止固体电极表现活性物质的相变、脱落、变形等弊端，有利于延长电极的寿命，该电极体系可     

锂电池极片微结构优化及可控制备技术进展

锂离子电池是应用最广泛的电化学储能器件,目前,经济的快速发展对其提出了更高的要求。 电极微观结构对电池性能影响显著,电极微结构精细设计及可控制备成为锂离子电池领域的研究热点之一。 本文结合锂离子电池最新发展趋势,总结了锂离子电池电极反应基本过程及电极微结构的表征技术,然后概述了近几年电极微观结构的设计与优化,并分析了电极微结构的关键特征。 基于理想的电极结构,综述了电极可控制备技术的最新进展。     

In situ compression and X-ray computed tomography of flow battery electrodes

Redox flow batteries offer a potential solution to an increase in renewable energy generation on the grid by offering long-term, large-scale storage and regulation of power. However, they are currently underutilised due to cost and performance issues, many of which are linked to the microstructure of the porous carbon electrodes used. Here, for the first time, we offer a detailed study of the in situ effects of compression on a commercially available carbon felt electrode. Visualisation of electrode structure using X-ray computed tomography shows the non-linear way that these materials compress and various metrics are used to elucidate the changes in porosity, pore size distribution and tortuosity factor under compressions from 0%-90%.     

钠离子电池微/纳结构电极材料研究

钠离子电池电极材料资源丰富,价格低廉. 然而,现阶段钠离子电池电极材料的性能还不理想,开发合适的电极材料是实现髙容量、长循环寿命钠离子电池的关键. 本文将以作者近期的研究工作为主,着重讨论几种微/纳米材料作为钠离子电池电极的性能及作用机理,并展望其今后的发展趋势.     

A new lead single flow battery in a composite perchloric acid system with high specific surface capacity for large-scale energy storage

In this paper, we propose a full lead single flow battery with ultra-high specific surface capacity, which is achieved by the combined effects of electrochemically deposited lead as a negative electrode, electrodeposited PbO₂ on Pt-plated titanium (Pt/Ti) plate as a positive electrode, and the composite perchloric acid with additives as an electrolyte. Experimental results indicate that this newly developed single flow battery provides a specific surface capacity of 125 mAh cm^?2, five times higher than that of the traditional lead single flow batteries using methanesulfonic acid or fluoroboric acid. The new lead single flow battery shows a good cycling performance with an average capacity efficiency of 95% and an energy efficiency of 85% after 500 cycles.     

A review of transition metal chalcogenide/graphene nanocomposites for energy storage and conversion

Recent advances in the applications of transition metal chalcogenides/graphene (TMC/graphene) nanocomposites in future energy storage and conversion are reviewed. The synthesis processes and structures of TMC/graphene, workingpriciple of evergy energy device, and the electrochemical performances are summarized.     

Material Design Concept of Lithium‐Excess Electrode Materials with Rocksalt‐Related Structures for Rechargeable Non‐Aqueous Batteries

Dependence on lithium‐ion batteries for automobile applications is rapidly increasing, and further improvement, especially for positive electrode materials, is indispensable to increase energy density of lithium‐ion batteries. In the past several years, many new lithium‐excess high‐capacity electrode materials with rocksalt‐related structures have been reported. These materials deliver high reversible capacity with cationic/anionic redox and percolative lithium migration in the oxide/oxyfluoride framework structures, and recent research progresses on these electrode materials are reviewed. Material design strategies for these lithium‐excess electrode materials are also described. Future possibility of high‐energy non‐aqueous batteries with advanced positive electrode materials is discussed for more details.     

The origin of potential rise during charging of Li-O_2 batteries

When aprotic Li-O_2 batteries recharge, the solid Li_2O_2 in the positive electrode is oxidized, which often exhibits a continuous or step increase in the charging potential as a function of the charging capacity, and its origin remains incompletely understood.Here, we report a model study of electro-oxidation of a Li_2O_2 film on an Au electrode using voltammetry coupled with in situ Raman spectroscopy. It was found that the charging reaction initializes at the positive electrode|Li_2O_2 interface, instead of the previously presumed Li_2O_2 surface, and consists of two temporally and spatially separated Li_2O_2 oxidation processes, accounting for the potential rise during charging of Li-O_2 batteries. Moreover, the electrode surface-initialized oxidation can disintegrate the Li_2O_2 film resulting in a loss of Li_2O_2 into electrolyte solution, which drastically decreases the charging efficiency and highlights the importance of using soluble electro-catalyst for the complete charging of Li-O_2 batteries.     

Critical aspects in the development of lithium–air batteries

Intensive research has been done on lithium–air batteries, especially in the last few years. Due to their very high theoretical specific energy, lithium–air batteries are one of the most promising candidates to power future electric vehicles. However, this new technology is in a very early stage of development, and several challenges must be overcome before there will be a commercially viable product. This review describes the most important critical aspects in the development of lithium–air batteries: the electrocatalysis of the oxygen electrode reactions, the degradation of the electrolyte and the oxygen electrode components, the structure of the oxygen electrode, and the passivation of the oxygen electrode during the discharge of the battery. Recent works in these areas are critically reviewed, and suitable research strategies to address these issues are discussed.