Rechargeable multivalent metal (e.g., Ca, Mg or, Al) batteries are ideal candidates for large-scale electrochemical energy storage due to their intrinsic low cost. However, their practical ...application is hampered by the low electrochemical reversibility, dendrite growth at the metal anodes, sluggish multivalent-ion kinetics in metal oxide cathodes and, poor electrode compatibility with non-aqueous organic-based electrolytes. To circumvent these issues, here we report various aqueous multivalent-ion batteries comprising of concentrated aqueous gel electrolytes, sulfur-containing anodes and, high-voltage metal oxide cathodes as alternative systems to the non-aqueous multivalent metal batteries. This rationally designed aqueous battery chemistry enables satisfactory specific energy, favorable reversibility and improved safety. As a demonstration model, we report a room-temperature calcium-ion/sulfur| |metal oxide full cell with a specific energy of 110 Wh kg
and remarkable cycling stability. Molecular dynamics modeling and experimental investigations reveal that the side reactions could be significantly restrained through the suppressed water activity and formation of a protective inorganic solid electrolyte interphase. The unique redox chemistry of the multivalent-ion system is also demonstrated for aqueous magnesium-ion/sulfur||metal oxide and aluminum-ion/sulfur||metal oxide full cells.
Abstract
The practical applications of lithium metal anodes in high-energy-density lithium metal batteries have been hindered by their formation and growth of lithium dendrites. Herein, we discover ...that certain protein could efficiently prevent and eliminate the growth of wispy lithium dendrites, leading to long cycle life and high Coulombic efficiency of lithium metal anodes. We contend that the protein molecules function as a “self-defense” agent, mitigating the formation of lithium embryos, thus mimicking natural, pathological immunization mechanisms. When added into the electrolyte, protein molecules are automatically adsorbed on the surface of lithium metal anodes, particularly on the tips of lithium buds, through spatial conformation and secondary structure transformation from α-helix to β-sheets. This effectively changes the electric field distribution around the tips of lithium buds and results in homogeneous plating and stripping of lithium metal anodes. Furthermore, we develop a slow sustained-release strategy to overcome the limited dispersibility of protein in the ether-based electrolyte and achieve a remarkably enhanced cycling performance of more than 2000 cycles for lithium metal batteries.
Water‐in‐salt (WIS) electrolytes using super‐concentrated organic lithium (Li) salts are of interest for aqueous Li‐ion batteries. However, the high salt cost, high viscosity, poor wettability, and ...environmental hazards remain a great challenge. Herein, we present a localized water‐in‐salt (LWIS) electrolyte based on low‐cost lithium nitrate (LiNO3) salt and 1,5‐pentanediol (PD) as inert diluent. The addition of PD maintains the solvation structure of the WIS electrolyte, improves the electrolyte stability via hydrogen‐bonding interactions with water and NO3− molecules, and reduces the total salt concentration. By in situ gelling the LWIS electrolyte with tetraethylene glycol diacrylate (TEGDA) monomer, the electrolyte stability window can be further expanded to 3.0 V. The as‐developed Mo6S8|LWIS gel electrolyte|LiMn2O4 (LMO) batteries delivered outstanding cycling performance with an average Coulombic efficiency of 98.53 % after 250 cycles at 1 C.
We present a localized water‐in‐salt gel electrolyte with low‐cost and high safety for aqueous lithium‐ion batteries. This electrolyte was fabricated by in situ gelling TEGDA monomer in an aqueous solution based on inexpensive LiNO3 salt and PD diluent. The as‐developed Mo6S8 | LWIS gel | LMO batteries delivered outstanding cycling performance with a Coulombic efficiency of 98.53 % % after 250 cycles at 1 C.
The deployment of high‐energy‐density lithium‐metal batteries has been greatly impeded by Li dendrite growth and safety concerns originating from flammable liquid electrolytes. Herein, we report a ...stable quasi‐solid‐state Li metal battery with a deep eutectic solvent (DES)‐based self‐healing polymer (DSP) electrolyte. This electrolyte was fabricated in a facile manner by in situ copolymerization of 2‐(3‐(6‐methyl‐4‐oxo‐1,4‐dihydropyrimidin‐2‐yl)ureido)ethyl methacrylate (UPyMA) and pentaerythritol tetraacrylate (PETEA) monomers in a DES‐based electrolyte containing fluoroethylene carbonate (FEC) as an additive. The well‐designed DSP electrolyte simultaneously possesses non‐flammability, high ionic conductivity and electrochemical stability, and dendrite‐free Li plating. When applied in Li metal batteries with a LiMn2O4 cathode, the DSP electrolyte effectively suppressed manganese dissolution from the cathode and enabled high‐capacity and a long lifespan at room and elevated temperatures.
Safety first: A deep eutectic solvent (DES)‐based self‐healing polymer electrolyte with high safety for lithium metal batteries was fabricated in situ by integrating an UPyMA‐PETEA copolymer matrix with a nonflammable DES+FEC electrolyte (see picture; FEC=fluoroethylene carbonate). The multifunctional electrolyte showed high ionic conductivity, stable interfacial characteristics without dendrite formation, and stable cycling in lithium metal batteries.
The family of 2D transition metal carbides, nitrides, and carbonitrides (collectively called MXenes) is rapidly studied since the initial synthesis of Ti3C2Tx (MXene). The surface of MXenes etched by ...hydrofluoric acid has hydrophilic groups (F, OH, and O), which leads the surface to be negatively charged. Consequently, the negatively charged surface can facilitate the compounding of MXenes with other positively charged materials and prevent MXenes from aggregating with some negatively charged substances, thus promoting the formation of a stable dispersion. The MXene‐based composites have better electrochemical performance than both precursors due to synergistic effects. This review elaborates and discusses the development of MXene‐based composites. It is aimed to summarize the various methods of fabricating MXene‐based composites. The applications of MXene‐based composites in batteries and supercapacitors are presented along with analysis of their excellent electrochemical performances. Finally, the authors propose the approach for further enhancing the electrochemical performances of MXene‐based composite electrode materials.
After the discussion of synthesis methods, structures, and properties of MXenes, different kinds of MXene‐based composites are introduced. Thereafter, the article focuses on their synthesis methods and applications in batteries and supercapacitors. Furthermore, the ways to improve the electrochemical performance of MXene‐based composites are also analyzed. Finally, some suggestions for improving the electrochemical performance of MXenes are proposed.
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.
This review provides the latest progress in emerging non‐flammable liquid electrolytes, including non‐flammable organic liquid electrolytes, aqueous electrolytes, and deep eutectic solvent‐based electrolytes, and systematically introduce their flame‐retardant mechanisms and electrochemical behaviors in alkali metal‐based batteries. Furthermore, the gelation techniques for quasi‐solid electrolyte preparation are thoroughly summarized. This review will promote the safety improvement of alkali metal‐based batteries.
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Magnesium-ion batteries (MIBs) are considered strong candidates for next-generation energy-storage systems owing to their high theoretical capacity, divalent nature and the natural ...abundancy of magnesium (Mg) resources on Earth. However, the development of MIBs has been mainly limited by the incompatibility of Mg anodes with several Mg salts and conventional organic-liquid electrolytes. Therefore, one major challenge faced by MIBs technology lies on developing safe electrolytes, which demonstrate appropriate electrochemical voltage window and compatibility with Mg anode. This review discusses the development of MIBs from the point-of-view of the electrolyte syntheses. A systematic assessment of promising electrolyte design strategies is proposed including liquid and solid-state electrolytes. Liquid-based electrolytes have been largely explored and can be categorized by solvent-type: organic solvent, aqueous solvent, and ionic-liquids. Organic-liquid electrolytes usually present high electrochemical and chemical stability but are rather dangerous, while aqueous electrolytes present high ionic conductivity and eco-friendliness but narrow electrochemical stability window. Some ionic-liquid electrolytes have proved outstanding performance but are fairly expensive. As alternative to liquid electrolytes, solid-state electrolytes are increasingly attractive to increase energy density and safety. However, improving the ionic conductivity of Mg ions in these types of electrolytes is extremely challenging. We believe that this comprehensive review will enable researchers to rapidly grasp the problems faced by electrolytes for MIBs and the electrolyte design strategies proposed to this date.
As promising alternatives to lithium-ion batteries, rechargeable anion-shuttle batteries (ASBs) with anions as charge carriers stand out because of their low cost, long cyclic lifetime, and/or high ...energy density. In this review, we provide for the first time, comprehensive insights into the anion shuttling mechanisms of ASBs, including anion-based rocking-chair batteries (ARBs), dual-ion batteries (DIBs), including insertion-type, conversion-type, and conversion-insertion-type, and reverse dual-ion batteries (RDIBs). Thereafter, we review the latest progresses and challenges regarding electrode materials and electrolytes for ASBs. In addition, we summarize the existing dilemmas of ASBs and outline the perspective of ASB technology for future grid storage.
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•Working mechanisms and characteristics of anion-shuttle batteries are summarized•Advances of electrode and electrolyte materials for anion-shuttle batteries are reviewed•Remaining challenges and future perspectives of anion-shuttle batteries are outlined
Lithium-ion batteries have so far remained the prevailing energy storage devices in mobile devices and electric vehicle markets. However, the relatively high cost of lithium and transition metal compounds in electrodes hinders their potential applications in grid energy storage. As an alternative energy storage strategy, rechargeable anion-shuttle batteries (ASBs) with anions, as charge carriers compensating charge neutrality of electrodes, have attracted great attention because of the prospect of low costs, long cycle life, and/or high energy density. Unraveling the anion-shuttle chemistries will benefit immensely the future development of high-performance batteries. This review presents a purview of emerging ASBs, including anion-based rocking-chair batteries (ARBs), dual-ion batteries (DIBs, including insertion-type, conversion-type, and conversion-insertion-type), and reverse dual-ion batteries (RDIBs). Their corresponding charge storage mechanisms, battery configurations, recent advances in electrode and electrolyte materials, challenges, and prospects are discussed in detail.
Anion-shuttle batteries (ASBs) with anions as charge carriers have attracted great attention because of the prospect of low cost, long cycle life, and/or high energy density. This review outlines the recent advances of different types of ASBs, i.e., anion-based rocking-chair batteries, dual-ion batteries (including insertion-type, conversion-type, and conversion-insertion-type), and reverse dual-ion batteries. We review the latest progresses and challenges regarding electrode materials and electrolytes and highlight the challenges and prospects of the ASB technology toward future grid energy storage.
Greenhouse gas emission related to the burning of fossil fuels for energy production is the main driver responsible for the climate crisis our society is facing. To avert climate change, the ...transition toward renewable energy production is urgent. However, the intermittence of these energy sources restrict their implementation. Coupling sustainable energy sources with energy storage systems could solve this issue. Since its commercialisation, Lithium (Li) -ion batteries have been at the centre of the attention for high-energy storage systems. As the global energy demand keeps increasing, new battery requirements are expected such as higher energy density and improved safety, which cannot be met by the current commercial Li-ion batteries. The thermally instable liquid electrolyte (containing highly flammable and toxic solvents, and thermally instable Li salts) usually employed in Li-ion batteries causes serious safety concerns. Many fires and explosions incidents occurred in the past few decades due to over-heating Li-ion batteries. Herein, various non-flammable electrolytes such as deep-eutectic-solvents and aqueous electrolytes were engineered to answer safety, dendrite growth and cost issues in Li and zinc (Zn) –based batteries. A fluorinated self-healing deep eutectic solvent quasi-solid electrolyte allowed long cycling performance of a Li-metal battery (Li||lithium manganese oxide (LiMn2O4, LMO) by creating a robust protective layer on the Li anode meanwhile the gel matrix helped guiding the Li deposition, thereby reducing dendrite growth and maintaining high safety. Then, a localized highly concentrated aqueous quasi-solid electrolyte was designed for low-cost Li-ion aqueous batteries with high voltage LMO cathode. Finally, a molecular crowding strategy was employed to suppress dendrite growth and corrosion on Zn metal anode in hybrid Zn||LMO aqueous batteries. These electrolyte designs opened up fascinating ways to tailor electrolyte properties for high safety and low-cost next battery generation.
A sulfur-rich copolymer has been prepared by utilizing two eco-friendly sources, squalene and sulfur. Chemical confinement of sulfur with squalene molecules can effectively suppress the active ...materials dissolution. The sulfur-rich copolymer was composited with 3D graphene-CNT network. The well-structured porous cathode can deliver an excellent electrochemical performance for lithium-sulfur battery cathodes.
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Lithium-sulfur (Li-S) batteries with high theoretical energy density and low cost are considered a promising energy storage system. However, great challenges still remain in achieving high sulfur loading and long cycle life. Herein we report a well-designed sulfur-rich copolymer@ 3D graphene-carbon nanotubes (G-CNT) network cathode for high-performance Li-S batteries. The sulfur-rich copolymer (87.29% sulfur) synthesised by inverse vulcanization between two eco-friendly sources, sulfur and squalene, can greatly suppress the dissolution of sulfur and polusulfides due to the chemical confinement from the crosslinking of polysulfur chains with the squalene molecules. The interlinked Sp2 G-CNT network can not only further enhance the polysulfide entrapment capability, but also provide the composite with an 3D electrical conductive path as well as an eminent mechanical resilience towards the huge volume change of sulfur. The as-developed cathode can deliver a high specific capacity of 1265 mAh g−1 at 0.2C with excellent rate performance and cycling stability (782 mAh g−1 at after 300 cycles at 1C).
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