Extending Cycle Life of Mg/S Battery by Activation of Mg Anode/Electrolyte Interface through an LiCl‐Assisted MgCl2 Solubilization Mechanism

Non‐nucleophilic electrolytes that can reversibly plate/strip Mg are essential for realizing high‐performance rechargeable Mg/S batteries. In contrast to organometallic electrolytes, all‐inorganic electrolytes based on MgCl₂‐AlCl₃ complexes are more cost‐effective and hold better stability to air and moisture. A recently developed electrolyte that contains tetrahydrofuran solvated divalent Mg cation, [Mg·6THF][AlCl₄]₂, has exhibited decent compatibility with the sulfur cathode. However, it suffers a large overpotential and short cycle life, which hinders its applications in Mg/S batteries. Here, an efficient plating/stripping of Mg is realized successfully by using LiCl to dissolve MgCl₂ from the electrolyte/electrode interface. As a result, the overpotential of Mg plating/stripping is remarkably reduced to 140/140 mV at a current density of 500 µA cm^?2. Both experiments and density functional theory (DFT) calculations reveal that the LiCl‐assisted solubilization of MgCl₂ facilitates the exposure of fresh surface on the Mg anode. Utilizing such an LiCl‐activation strategy, Mg/S full batteries with a significantly extended cycle life of over 500 cycles, as well as coulombic efficiency close to 100%, are achieved successfully. This work demonstrates the role of LiCl‐assisted interface activation on extending the cycle‐life Mg/S batteries with all‐inorganic electrolytes.     

Gel Polymer Electrolyte toward Large-Scale Application of Aqueous Zinc Batteries

Aqueous zinc batteries are promising candidates for energy storage and conversion devices in the “post-lithium” era due to their high energy density, high safety, and low cost. The electrolyte plays an important role in zinc batteries by conducting and separating the positive and negative electrodes. However, the issues of zinc dendrites growth, corrosion, by-product formation, hydrogen evolution and leakage, and evaporation of the aqueous electrolytes affect the commercialization of the batteries. Moreover, the widely used aqueous electrolytes result in large battery sizes, which are not conducive to the emerging smart devices. The intrinsic properties of gel polymer electrolytes (GPEs) can solve the above problems. In order to promote the wider application of GPEs-based zinc batteries, in this review, the working principle and the current problems of zinc batteries are first introduced, andthe merits of GPEs compared to aqueous electrolytes are then summarized. Subsequently, a series of challenges and corresponding strategies faced by GPE is discussed, and an outlook for its future development is finally proposed.     

High Performance Composite Polymer Electrolytes for Lithium-Ion Batteries

Today, there is an urgent demand to develop all solid-state lithium-ion batteries (LIBs) with a high energy density and a high degree of safety. The core technology in solid-state batteries is a solid-state electrolyte, which determines the performance of the battery. Among all the developed solid electrolytes, composite polymer electrolytes (CPEs) have been deemed as one of the most viable candidates because of their comprehensive performance. In this review, the limitations of traditional solid polymer electrolytes and the recent progress of CPEs are introduced. The effect and mechanism of inorganic fillers to the various properties of electrolytes are discussed in detail. Meanwhile, the factors affecting ionic conductivity are intensively reviewed. The recent representative CPEs with synthetic fillers and natural clay-based fillers are highlighted because of their great potential. Finally, the remaining challenges and promising prospects are outlined to provide strategies to develop novel CPEs for high-performance LIBs.     

Polymer-Based Solid Electrolytes: Material Selection,Design, and Application

Polymer-based solid electrolytes (PSEs) have attracted tremendous interests for the next-generation lithium batteries in terms of high safety and energy density along with good flexibility. Remarkable performances have been demonstrated in PSEs, which endowed PSEs with the potential to replace liquid electrolytes to meet the market demands. In this review, polymer matrices, different polymer architectures, and functional filler materials used in PSEs are discussed to explore the design concepts, methodologies, working mechanisms, and pros and cons of various PSEs. In addition, their recent notable applications in all-solid-state lithium ion batteries, lithium–sulfur batteries, suppression of lithium dendrites, and flexible lithium batteries are also introduced. Finally, the challenges and future prospects are sketched to provide strategies to explore novel PSEs for high-performance all-solid-state lithium batteries.     

A Trip to Oz and a Peak Behind the Curtain of Magnesium Batteries

The introduction of the Li‐ion battery has revolutionized the electronics industry due to its high energy density. Magnesium batteries may have the potential to exceed the energy densities of Li‐ion batteries. Herein, the major advancements in magnesium electrochemistry and the challenges that must be overcome to realize a practical magnesium battery are discussed. So too are the controversial realities of current magnesium battery research and their implications.     

离子液体在片式铝电解电容器中的应用研究

利用离子液体具有的高热稳定性、高离子电导率的特点,选用了几种离子液体用作片式铝电解电容器工作电解液。性能测试结果表明,以马来酸或邻苯二甲酸的1,3-二烷基取代的咪唑盐或四氢吡咯盐的离子液体为电解质,所制成的电容器能通过105℃1000h寿命试验和耐回流焊接热试验。但电解液的闪火电压与传统电解液相比较低,一般只能做50V以下的低压电容器产品。     

Complex Hydrides for Electrochemical Energy Storage

Complex hydrides have energy storage‐related functions such as i) solid‐state hydrogen storage, ii) electrochemical Li storage, and iii) fast Li‐ and Na‐ionic conductions. Here, recent progress on the development of fast Li‐ionic conductors based on the complex hydrides is reported. The validity of using them as electrolytes in all‐solid‐state lithium rechargeable batteries is also examined. Not only coated oxides but also bare sulfides are found to be applicable as positive electrode active materials. Results related to fast Na‐ionic conductivity in the complex hydrides are presented. In the last section, the future prospects for battery assemblies with high‐energy densities, and Mg ion batteries with the liquid and the solid‐state electrolytes are discussed.     

Incombustible Polymer Electrolyte Boosting Safety of Solid-State Lithium Batteries: A Review

Lithium-ion batteries with their portability, high energy density, and reusability are frequently used in today's world. Under extreme conditions, lithium-ion batteries leak, burn, and even explode. Therefore, improving the safety of lithium-ion batteries has become a focus of attention. Researchers believe using a solid electrolyte instead of a liquid one can solve the lithium battery safety issue. Due to the low price, good processability and high safety of the solid polymer electrolytes, increasing attention have been paid to them. However, polymer electrolytes can also decompose and burn under extreme conditions. Moreover, lithium dendrites are formed continuously due to the uneven charge distribution on the surface of the lithium metal anode. A short circuit caused by a lithium dendrite can cause the battery to thermal runaway. As a result, the safety of polymer solid-state batteries remains a challenge. In this review, the thermal runaway mechanism of the batteries is summarized, and the batteries abuse test standard is introduced. In addition, the recent works on the high-safety polymer electrolytes and the solution strategies of lithium anode problems in polymer batteries are reviewed. Finally, the development direction of safe polymer solid lithium batteries is prospected.     

Progress and Perspectives of Lithium Aluminum Germanium Phosphate-Based Solid Electrolytes for Lithium Batteries

Solid-state lithium batteries are considered promising energy storage devices due to their superior safety and higher energy density than conventional liquid electrolyte-based batteries. Lithium aluminum germanium phosphate (LAGP), with excellent stability in air and good ionic conductivity, has gained tremendous attention over the past decades. However, the poor interface compatibility with Li anode, slow Li-ion conduction in thick pellets, and high-temperature sintering procedure limit the further development of LAGP solid electrolytes in practical applications. This review comprehensively summarizes the crystal structure, Li-ion conducting mechanism, and various synthesis methods, especially the latest thin-film preparation approach. The underlying reason for Li/LAGP interfacial instability is identified, followed by several advanced interface engineering strategies, for example, introducing a functional interlayer. The integration design of LAGP-based solid electrolytes and cathode is also highlighted to enable high-loading cathodes. Additionally, recent progress of lithium-oxygen and lithium-sulfur batteries with LAGP-based solid electrolytes is discussed. Moreover, the different Li-ion migration pathways, preparation procedures, and electrochemical performance of polymer-LAGP composite solid electrolytes in Li-ion batteries are introduced. Lastly, the remaining challenges and opportunities are proposed to encourage more efforts in this field. This review aims to provide fundamental insights and promising directions toward practical LAGP-based solid-state batteries.     

Dual‐Salt Mg‐Based Batteries with Conversion Cathodes

Mg batteries as the most typical multivalent batteries are attracting increasing attention because of resource abundance, high volumetric energy density, and smooth plating/stripping of Mg anodes. However, current limitations for the progress of Mg batteries come from the lack of high voltage electrolytes and fast Mg‐insertable structure prototypes. In order to improve their energy or power density, hybrid systems combining Li‐driven cathode reaction with Mg anode process appear to be a potential solution by bypassing the aforementioned limitations. Here, FeS _x (x = 1 or 2) is employed as conversion cathode with 2–4 electron transfers to achieve a maximum energy density close to 400 Wh kg^?1, which is comparable with that of Li‐ion batteries but without serious dendrite growth and polysulphide dissolution. In situ formation of solid electrolyte interfaces on both sulfide and Mg electrodes is likely responsible for long‐life cycling and suppression of S‐species passivation at Mg anodes. Without any decoration on the cathode, electrolyte additive, or anode protection, a reversible capacity of more than 200 mAh g^?1 is still preserved for Mg/FeS₂ after 200 cycles.     

单取代磷酸酯在电解电容器中的应用

通过单取代磷酸酯 (简称 L HPR)与磷酸及其盐类在电解液中的作用效果之对比实验 ,研究了 L HPR对铝电解电容器性能的影响。结果表明 ,L HPR可以提高电解液的稳定性及耐压 ,降低电容器的漏电流。分析了L HPR在电解液中的作用机理 :(1)电子云密度大 ,容易吸附于氧化膜表面 ,非极性部分向外能阻止水分子靠近氧化膜 ;(2 )因其酸性弱 ,起缓蚀剂作用 ,从而对氧化膜产生修复和保护     

Great Challenges and New Paradigm of The In Situ Polymerization Technology Inside Lithium Batteries

In situ polymerization technology is expected to empower the next generation high specific energy lithium batteries with high safety and excellent cycling performance. Nevertheless, the large-scale commercial applications of most reported in situ polymer electrolytes are still full of challenges. Owing to the severe parasitic reactions caused by residual monomers, additional initiators and oligomers, lithium batteries using in situ polymer electrolytes often demonstrate limited specific capacity, poor cycling performance, and insufficient rate capability. However, this issue has not received adequate attention in previous reports. Furthermore, the design and evaluation of in situ polymer electrolytes still lack effective guidance and unified standards. Herein, the development history of in situ polymer electrolytes are systematically reviewed and critically disclose the great challenges. Then, from the aspects of monomers, initiators, separators, manufacturing technologies, safety and cycle life evaluation, unprecedentedly a new paradigm is provided for upgrading the in situ polymerization technology inside lithium batteries. It is hoped the novel paradigm will prompt much more insightful studies, expediting the commercialization of in situ polymerization technology in lithium batteries.     

Sustainable Dough-Based Gel Electrolytes for Aqueous Energy Storage Devices

Polymer gel electrolytes are usually utilized in various energy storage devices due to their advantages of excellent ionic conductivity and outstanding mechanical properties. However, they are often not biodegradable and lose their flexibility and electrochemical performance during the dehydration/hydration process. Herein, sustainable dough-based gel electrolytes with high biosafety and environmental friendliness are developed. In the dough electrolytes, gluten molecules connect with each other through disulfide bonds to construct gluten network and water that contains abundant ions adheres on it to achieve a continuous ion transport pathway. Therefore, the dough electrolytes possess outstanding mechanical properties and excellent ionic conductivities. More impressively, they also exhibit the ability to recover their electrochemical and mechanical performance after dehydration/hydration cycles as well as the self-adhering, degradable, and edible behaviors. As a proof of concept, the dough electrolytes are used in supercapacitors and zinc-ion batteries. The resultant devices display comparable electrochemical performance in comparison with the counterparts with polymer gel electrolytes. Furthermore, the multiple functions of dough electrolytes are also integrated into the supercapacitors and zinc-ion batteries devices. This work provides a promising route to design highly sustainable gel electrolytes for different aqueous energy storage devices.     

导电聚苯胺在铝电解电容器中的应用

导电高分子在电子元件中的应用十分广泛。比较了几种用于铝电解电容器中的固体电解质:二氧化锰、TCNQ、聚吡咯、聚苯胺,其中聚吡咯、聚苯胺的性能优势明显,尤其是聚苯胺的电导率和热稳定性最好。介绍了聚苯胺结构特征、合成方法以及聚苯胺铝电解电容器的制造方法和性能,展望了聚苯胺的应用前景。     

Composition and Structure Design of Poly(vinylidene fluoride)-Based Solid Polymer Electrolytes for Lithium Batteries

Solid-state lithium batteries have become the focus of the next-generation high-safety lithium batteries due to their dimensional, thermal, and electrochemical stability. Thus, the progress of solid electrolytes with satisfactory comprehensive performances has become the key to promoting the development of solid batteries. Herein, poly(vinylidene fluoride) (PVDF) solid polymer electrolytes (SPEs) possess excellent flexibility, mechanical property, and high electrochemical and thermal stability, which show huge application potentiality in solid-state lithium batteries and obtain extensive research. But the PVDF SPEs have been suffering from low ionic conductivity, high crystallinity, and low reactive sites. The development of PVDF-based composite solid polymer electrolytes (CSPEs) has been confirmed to be a forceful strategy to optimize the performance of electrolytes. In this review, based on different design strategies, the recent progress of PVDF-based SPEs is introduced in detail, especially in the mechanism of ionic conductivity enhancement and interface regulation by modified fillers. Besides, the applications of PVDF-based SPEs in Li-S and Li-O₂ battery systems are also introduced. Finally, this review presents some insights for promoting the development of high-performance PVDF-based SPEs.     

Electrochemical vehicle power plants

The requirement of high energy density for vehicle applications leads to the selection of battery systems made up of light, highly reactive metals found in the upper-left-hand corner of the periodic table for one electrode and the light oxidizers found in the top-right-hand corner of the periodic table for the other electrode. Many of these reactive materials will react with water and hence water-based electrolytes cannot be used in such systems. Electric vehicles also require the battery to have a high power density, which further limits the use of water-based electrolytes. The parameters relevant to achieving high-energy, high-power batteries are discussed in general terms and several systems presently being studied are reviewed.     

高频低阻抗长寿命无极性铝电解电容器的研制

从铝电解电容器的基本性能分析入手，对高频低阻抗无极性铝电解电容器的特性进行了分析和讨论，开发出新型的工作电解液，并选择合适的材料，研制出了可用于８５℃，３０００ｈ的高频低阻抗无极性铝电解电容器。     

Advanced Liquid Electrolytes for Rechargeable Li Metal Batteries

Rechargeable lithium metal batteries (LMBs) have attracted wide attention for future electric vehicles and next‐generation energy storage because of their exceptionally high specific energy density. Recently, the development of electrode materials for LMBs has been extensively discussed and reviewed in the literature, but there have been very few reports that systematically review the status and progress of electrolytes for such applications. Actually, the viability of practical LMBs critically depends on the development of suitable liquid electrolytes due to the high reactivity of Li metals toward most solvents. This paper provides a systematic summary of the background and recent advances of the electrolytes for LMBs with an emphasis on the thermodynamic and kinetic stabilities at the interfaces. In addition, the emerging advanced characterization techniques for understanding the electrolyte–electrode interfaces are surveyed. Finally, a perspective for future directions is provided.     

Rechargeable Magnesium–Sulfur Battery Technology: State of the Art and Key Challenges

Inspired by the first rechargeable Mg battery about 20 years ago, based on a Chevrel phase cathode, a Mg foil anode, and a magnesium organo‐aluminate electrolyte, research on rechargeable batteries using sulfur as the cathode together with Mg as the anode has gained substantial and increasing interest. In particular, the safety characteristics of magnesium–sulfur (Mg–S) batteries, the high abundance of both magnesium and sulfur, and the high theoretical volumetric energy density of magnesium render this system specifically interesting for mobile applications that require high volumetric energy densities, i.e., the automotive and aviation sector. While the development of Mg–S batteries is still at a nascent stage, some breakthroughs have already been accomplished. Consequently, it appears necessary to provide a comprehensive up‐to‐date review about the current achievements to facilitate further improvements in this field. In this review, the state of the art in Mg–S batteries is summarized, focusing on sulfur conversion cathodes, magnesium anode materials, currently employed electrolyte systems, as well as on current collectors and separator design. In addition, the challenges and some possible future work to realize a practically applicable and technically viable Mg–S battery are highlighted.     

Non-Flammable Liquid and Quasi-Solid Electrolytes toward Highly-Safe Alkali Metal-Based Batteries

Rechargeable alkali metal (i.e., lithium, sodium, potassium)-based batteries are considered as vital energy storage technologies in modern society. However, the traditional liquid electrolytes applied in alkali metal-based batteries mainly consist of thermally unstable salts and highly flammable organic solvents, which trigger numerous accidents related to fire, explosion, and leakage of toxic chemicals. Therefore, exploring non-flammable electrolytes is of paramount importance for achieving safe batteries. Although replacing traditional liquid electrolytes with all-solid-state electrolytes is the ultimate way to solve the above safety issues, developing non-flammable liquid electrolytes can more directly fulfill the current needs considering the low ionic conductivities and inferior interfacial properties of existing all-solid-state electrolytes. Moreover, the electrolyte leakage concern can be further resolved by gelling non-flammable liquid electrolytes to obtain quasi-solid electrolytes. Herein, a comprehensive review of the latest progress in emerging non-flammable liquid electrolytes, including non-flammable organic liquid electrolytes, aqueous electrolytes, and deep eutectic solvent-based electrolytes is provided, and systematically introduce their flame-retardant mechanisms and electrochemical behaviors in alkali metal-based batteries. Then, the gelation techniques for preparing quasi-solid electrolytes are also summarized. Finally, the remaining challenges and future perspectives are presented. It is anticipated that this review will promote a safety improvement of alkali metal-based batteries.