Rechargeable Li Batteries Research Articles

Application Progress of Polyaniline, Polypyrrole and Polythiophene in Lithium-Sulfur Batteries.

With the urgent requirement for high-performance rechargeable Li-S batteries, besides various carbon materials and metal compounds, lots of conducting polymers have been developed and used as components in Li-S batteries. In this review, the synthesis of polyaniline (PANI), polypyrrole (PPy) and polythiophene (PTh) is introduced briefly. Then, the application progress of the three conducting polymers is summarized according to the function in Li-S batteries, including coating layers, conductive hosts, sulfur-containing compounds, separator modifier/functional interlayer, binder and current collector. Finally, according to the current problems of conducting polymers, some practical strategies and potential research directions are put forward. We expect that this review will provide novel design ideas to develop conducting polymer-containing high-performance Li-S batteries.

Correction: The role of substituents in determining the redox potential of organic electrode materials in Li and Na rechargeable batteries: electronic effects vs. substituent-Li/Na ionic interaction

Correction for ‘The role of substituents in determining the redox potential of organic electrode materials in Li and Na rechargeable batteries: electronic effects vs. substituent-Li/Na ionic interaction’ by Sechan Lee et al., J. Mater. Chem. A, 2019, 7, 11438–11443.

Electrospinning techniques for Li, Na and K-ion batteries

Abstract In this current outlook, we critically review the most vital new outcomes in the field of rechargeable Li, Na and K-ion batteries. We deliberate current discoveries like the progress of electrospinning and their applications in future. Mainly, we discuss freestanding and binder-free electrodes structural and morphological effect when it undergoes long term cycling. Finally, this short review grants the up-to-date advancement on novel processing strategies of various carbon-based electrospun composites as anodes whose performance are similar with or even can beat that of the commercial anode material system.

Advances in the Cathode Materials for Lithium Rechargeable Batteries.

The accelerating development of technologies requires a significant energy consumption, and consequently the demand for advanced energy storage devices is increasing at a high rate. In the last two decades, lithium-ion batteries have been the most robust technology, supplying high energy and power density. Improving cathode materials is one of the ways to satisfy the need for even better batteries. Therefore developing new types of positive electrode materials by increasing cell voltage and capacity with stability is the best way towards the next-generation Li rechargeable batteries. To achieve this goal, understanding the principles of the materials and recognizing the problems confronting the state-of-the-art cathode materials are essential prerequisites. This Review presents various high-energy cathode materials which can be used to build next-generation lithium-ion batteries. It includes nickel and lithium-rich layered oxide materials, high voltage spinel oxides, polyanion, cation disordered rock-salt oxides and conversion materials. Particular emphasis is given to the general reaction and degradation mechanisms during the operation as well as the main challenges and strategies to overcome the drawbacks of these materials.

Catalytic effect of reduced graphene oxide on facilitating reversible conversion reaction in SnO2 for next-generation Li rechargeable batteries

With growing needs for mobility and wearable devices, developing advanced electrode materials for next-generation Li rechargeable batteries becomes one of the major challenges. To resolve this issue, various types of metal oxide materials have been adopted as high-capacity anode materials. In this work, a high-energy SnO2-based anode material is proposed by combinative hybridization with reduced graphene oxide, which is an efficient method to improve electrochemical performance of Li-ion battery. As a result, the Li storage performance of SnO2 and reduced graphene oxide composite electrode is remarkably enhanced in terms of reversible capacity, cyclability and rate capability. Synchrotron-based X-ray analysis has revealed that the improvement in electrochemical performances can be attributed to high and stable participation of additional conversion reaction as well as alloying reaction of SnO2 along with insertion reaction of reduced graphene oxide. In this composite electrode, we observe catalytic effect of reduced graphene oxide that improves reversibility of conversion reaction by reducing Sn–O bond strength, in addition to providing stable matrix. The information from this work will give insights into how the changes of physicochemical properties in graphene composite materials affect the electrochemical performance of electrode material and thus, provide a realizable strategy for next-generation rechargeable batteries.

In Situ Formed Ir3Li Nanoparticles as Active Cathode Material in Li-Oxygen Batteries.

Lithium-oxygen (Li-O2) batteries are a promising class of rechargeable Li batteries with a potentially very high achievable energy density. One of the major challenges for Li-O2 batteries is the high charge overpotential, which results in a low energy efficiency. In this work size-selected subnanometer Ir clusters are used to investigate cathode materials that can help control lithium superoxide formation during discharge, which has good electronic conductivity needed for low charge potentials. It is found that Ir particles can lead to lithium superoxide formation as the discharge product with Ir particle sizes of ∼1.5 nm giving the lowest charge potentials. During discharge these 1.5 nm Ir nanoparticles surprisingly evolve to larger ones while incorporating Li to form core-shell structures with Ir3Li shells, which probably act as templates for growth of lithium superoxide during discharge. Various characterization techniques including DEMS, Raman, titration, and HRTEM are used to characterize the LiO2 discharge product and the evolution of the Ir nanoparticles. Density functional calculations are used to provide insight into the mechanism for formation of the core-shell Ir3Li particles. The in situ formed Ir3Li core-shell nanoparticles discovered here provide a new direction for active cathode materials that can reduce charge overpotentials in Li-O2 batteries.

Plating/Stripping Behavior of Actual Lithium Metal Anode

AbstractLithium (Li) metal anodes exhibits the potential to enable rechargeable Li batteries with a high energy density. However, the irreversible plating and stripping behaviors of Li metal anodes with high reactivity and dendrite growth when matching different cathodes in working cells are not fully understood yet. Herein the working manner of very thin Li metal anodes (50 µm, 10 mAh cm−2) is probed with different sequences of Li plating and stripping at 3.0 mA cm−2 and 3.0 mAh cm−2. Dendrite growth and dead Li forms on the surface of the initially plated Li electrode (P‐Li), while Li dendrites form in the pit of the initially stripped Li electrode (S‐Li). This induces the differences in reactive sites, distribution of dead Li, and voltage polarization of Li metal anodes. There is a gap of 15–20 and 13–16 mV for the end voltages between S‐Li and P‐Li during stripping and plating, respectively. When matching LiFePO4 and FePO4 cathodes, P‐Li | LiFePO4 cells exhibit a 30‐cycle longer lifespan with smaller end polarization due to differences in the sequences of Li plating and stripping. This contribution affords emerging working principles for actual Li metal anodes when matching lithium‐containing and lithium‐free cathodes.

Mixed-metal borate FeVBO4 of tunnel structure: Synthesis and electrochemical properties in lithium and sodium ion batteries

Transition borates exhibit various functions due to their diverse components and structures. Herein, a new mixed-metal borate, FeVBO4 with rhombic and triangular tunnels for ionic transportation, is first synthesized at 800 °C subsequent to a sol-gel routine. The new compound FeVBO4 crystallizes in an orthorhombic space group (Pnma, #62), with cell parameters of a = 9.2367(5) Å, b = 3.1772(1) Å, and c = 9.3912(6) Å. Furthermore, the electrochemical properties of carbon-coated FeVBO4 (FeVBO4/carbon) is evaluated as intercalated anode for rechargeable Li and Na batteries. The Na storage of FeVBO4/carbon via conversion reaction exhibits very low reversible capacity (46 mAh g−1). However, the Li storage of FeVBO4/carbon revealing high capacity is worth to investigate. The Li ions first insert the rhombic tunnels to form the LixFeVBO4 (0 < x ≤ 1) solid solution, and then squeeze into the triangular tunnel and activate a conversion reaction accomplished by delivering a high discharge capacity of 621.6 mAh g−1 (theoretical capacity 737.9 mAh g−1) and showing a reversible recharge capacity of 387.3 mAh g−1. Our study has unlocked the great potential of borate-type anode in rechargeable batteries, and the new compound FeVBO4 with unique structure and mixed metallic elements could be extended to other application area.

Fabrication and Characterization of High Capacity and Long Cycle Life Lithium-Sulfur Battery Using Porous Material As a Polysulfide Adsorbent

The need for large-scale energy storage, improved safety, and sustainable transport are driving research into alternative battery technologies with higher specific energies. Rechargeable Li-S batteries have high capacities (1675 mAh g-1) and theoretical energy densities as high as 2600 Wh kg-1 making them promising candidates for the next-generation of energy storage systems. However, due to its insulating nature, polysulfide dissolution and poor cycle life, it has been challenging to achieve the existing technology requirement. Herein we choose porous carbon as conducting agent and TiO2 nanotube as polysulfide adsorbent and forming hybrid nanostructured materials to overcome active material utilization and polysulfide dissolution problems. The porous host materials for sulfur was produced by a low cost, hydrothermal and annealing process with one step green synthesis approach. The process is facile, cheap, scalable and environmental friendly. The material was characterized and examined by XRD, BET, XPS, SEM, TEM, Raman, TGA, CV, EIS and galvanostatic charge-discharge tastes. It is found that the materials are highly porous and show both the characteristics of microporous and mesoporous behavior and contain large pore volume to impregnate large amount of sulfur. Moreover, the microporous carbon can effectively adsorb smaller sulfur (S2-4) molecules in their narrow pores with increasing the electrical conductivity of the cathode by decreasing the resistance of sulfur and enhance active material utilization. Meanwhile, mesoporous carbon doped TiO2 nanotube were placed on the surface to prevent the overflow of sulfur as well as the dissolution of polysulfides in the electrolyte effectively and improve the strength of the entire electrode thereby enhancing the electrochemical performance. As a result, using the porous host-sulfur nanocomposite as a cathode material, we demonstrate excellent cycle stability with initial discharge capacity of 916 mAh g-1 with coulombic efficiency of over 98.6% at a current density of 0.2 C after 140 cycles. This improved performance is due to the unique design of the porous host materials and the good dispersion of sulfur in the narrow pores of microporous host with TiO2 support. Thus, our approach is a promising strategy to control the dissolution of polysulfides and cycle life problems of the battery. Key words: porous materials, lithium-sulfur battery, polysulfide adsorbent, cycle stability

Single Atoms for Energy Applications

Single Atoms for Energy Applications

Polymer-free electrospun separator film comprising silica nanofibers and alumina nanoparticles for Li-ion full cell

Abstract A separator film for high-performance Li-ion batteries was prepared by electrospinning. The film had a hybrid morphology of silica nanofibers (SNFs) and alumina nanoparticles (ANPs), with a smooth surface, polymer-free composition, high porosity (79%), high electrolyte uptake (876%), and excellent thermal stability. Contact angle measurements demonstrated the better immersion capability of the SNF-ANP separator film for commercial liquid electrolytes than a commercial CELGARD 2500 separator film. Moreover, compared to the commercial CELGARD 2500 separator, the ionic conductivity of the SNF-ANP separator film was nearly three times higher, the bulk resistance was lower at elevated temperature (120 °C), the interfacial resistance with lithium metal was lower, and the electrochemical window was wider. Full cells were fabricated to determine the cell performance at room temperature. The specific capacity of the full cell with the SNF-ANP separator film was 165 mAh g−1; the cell was stable for 100 charge/discharge cycles and exhibited a capacity retention of 99.9%. Notably, the electrospun SNF-ANP separator film can be safely used in Li-ion or Li-S rechargeable batteries.

Building egg-tray-shaped graphenes that have superior mechanical strength and band gap

The major hindrances of implementing graphene in two-dimensional (2D) electronics are both mechanical (the tendency to crumble and form ripples) and electrical (the lack of a band gap). Moreover, the inevitable structural defects in graphene have a profound influence on its physical and chemical properties. Here, we propose a family of 2D egg-tray graphenes constructed by arranging pentagon and heptagon defects in the graphene lattice based on a careful analysis of the topological distribution of minima, maxima, and saddle points. First-principles calculations show that the egg-tray graphenes are dynamically stable, and their energies, which depend on the concentration of pentagons and heptagons, are the lowest among carbon allotropes. These 2D carbon allotropes exhibit a large variation in their electronic properties, ranging from semimetallic to semiconducting, including some allotropes that have Dirac cones in their band structures. Furthermore, some egg-tray graphenes are predicted to have negative Poisson’s ratios. The adsorption of Li atoms on the egg-tray graphenes is considerably stronger than the adsorption on perfect graphene, therefore they may absorb Li more effectively than graphene, which is important for improving the performance of rechargeable Li batteries.

Carbon Nanofibers Modified By Natural Pectic Polysaccharide As the Multifunctional Interlayer for Advanced Li-SeS2 Batteries

In order to satisfy the ever-growing demand of higher energy densities for electric vehicles and consumer electronics, high-performance rechargeable batteries have attracted remarkable attentions in the last ten years. Recently, rechargeable Li-S batteries have captured intensive attention for high theoretical energy density and cost effective materials.[1] However, there is a certain distance to achieve the practical application of Li-S batteries due to some pivotal issues that are demanded of being disposed promptly: 1) the connatural poor electroconductivity of elemental sulfur and the end discharge products (Li2S/Li2S2), 2)a noticeable volume expansion in the lithiation process, 3) the shuttle effect of polysulfides (Li2Sn, 4≤n≤8).[2,3] Recently, researchers focus on the Se cathodes owing to the high electronic conductivity (1 X 10- 3 S m- 1) and the theoretical volumetric capacity (3253 mA h cm- 3) comparable to that of S (3467 mA h cm- 3). As the congener of S , Se has a similar (de)lithiation process to sulfur. However, the theoretical gravimetric capacity of Se (675 mA h g- 1) is much lower than that of S (1675 mA h g- 1).[4] To rationally balance the opposite but complementary features of Se and S, selenium sulfide (SeS2) has been proposed as a cathode for lithium ion batteries due to its theoretical mass capacity of 1345 mA h g- 1, which is close to that of sulfur, and its advantageous electronic conductivity as compared to sulfur. Since SeS2 has similar chemical properties to S, it is expected that the strategies used for stabilizing the S cathode might be also effective for suppressing the dissolution of lithium polysulfides/polyselenides in the SeS2 cathodes. To alleviate shuttling in high-sulfur-loading cathodes, improve sulfur utilization, and accelerate the redox reaction of polysulfides, a novel and advanced cell configuration has recently been developed by introducing a conductive interlayer between the sulfur cathode and the ordinary polymer separator. This inserted interlayer not only serves as an LPS trap, stabilizing LPSs within the cathode region, but also as a second current collector to reduce cell polarization and facilitate the redox kinetics.[5] In this contribution, pectic polysaccharide (named NPG), a natural polymer, is introduced to conductive carbon nanofibers (named CF) to build a free-standing CF-NPG composite interlayer via a solution-coating method. The pectic polysaccharide is isolated from the seed of Nicandra physaloides (L.) Gaertn by water extraction. The NPG have a backbone chain composed of 1→ 4 linked galacturonic acid with heavily branched glucose, galactose, and rhamnose side chains that can afford a strong binding interaction toward lithium polysulfdes and polyselenides through its rich hydroxyl, carboxyl, and ether functional groups.[6] Thus, the as-obtained CF-NPG composite interlayer can effectively impede the shuttle effect. In addition, the conductive composite interlayer, functioned as upper current collectors, can improve the SeS2 utilization, ensuring good cycling stability and rate capability. With the CF-NPG interlayers, the SeS2 cathodes with a high loading (70 wt%) demonstrat a good cyclability with a capacity retention of nearly 80% over 500 cycles. The SeS2 cathodes show excellent rate performances with capacities of 592 mA h g-1, 440 mA h g-1, and 350 mA h g-1 at 1A g-1, 5A g-1, and 10A g-1, respectively. In conclusion, a polysulfde-immobilizing polymer interlayer was firstly used for Li-SeS2 batteries, an effcient reuse of the adsorbed sulfides and selenides is realized and thus a high utilization of SeS2, which outperform most Li-SeS2 batteries reported in the literature. Figure 1 (a) the optical photographs of raw materials (nicandra physaloides seeds) (b) the SEM images of CF-PNG, (c) the cycle performance of SeS2 cathodes with CF-PNG interlayers. [1] Manthiram A, Fu Y, Su Y S. Challenges and prospects of lithium–sulfur batteries. Accounts of chemical research, 2012, 46(5): 1125-1134. [2] Liang X, Hart C, Pang Q, et al. A highly efficient polysulfide mediator for lithium–sulfur batteries. Nature communications, 2015, 6: 5682. [3] Fang R, Zhao S, Sun Z, et al. More Reliable Lithium‐Sulfur Batteries: Status, Solutions and Prospects. Advanced Materials, 2017, 29(48): 1606823. [4] He J, Lv W, Chen Y, et al. Direct impregnation of SeS 2 into a MOF-derived 3D nanoporous Co–N–C architecture towards superior rechargeable lithium batteries. Journal of Materials Chemistry A, 2018, 6(22): 10466-10473. [5] Guo Y, Zhang Y, Zhang Y, et al. Interwoven V 2 O 5 nanowire/graphene nanoscroll hybrid assembled as efficient polysulfide-trapping-conversion interlayer for long-life lithium–sulfur batteries. Journal of Materials Chemistry A, 2018, 6(40): 19358-19370. [6] Niu Q F, Wang B, Li T, et al. Structure and Gel Characterizaction of Petic Polysaccharide from Nicandra physaloides (L.) Gaertn Seeds. Modern Food Science and Technology, 2015, 9: 68-73. Figure 1

Spherical Si-Nb2O5-C Composite As Anode Materials for Li Secondary Batteries

In recent years, Li-ion batteries have attracted much attention as the demand for electronics and electric vehicles has increased. Currently, graphite is used as anode materials for Li-ion batteries because of its good cycle performance and reasonable cost. However, graphite has a relatively low specific capacity of 372 mAhg-1 due to its lithium storage mechanism. The low theoretical capacity of graphite does not meet the consumer's need for batteries with high capacity. Therefore, development of new anode materials with high capacity are strongly required. Among diverse Li storage materials that can replace graphite, Li-alloy based materials including group IV elements have been widely researched due to their high theoretical capacity. In particular, silicon has attracted great attention as anode materials for Li-ion batteries due to its high capacity and natural abundance. However, silicon anodes generally suffer from volume expansion during the Li insertion and extraction process, which results in poor cycle performance. To overcome the problem, strategies to suppress the volume expansion of silicon should be suggested. In this work, we synthesized carbon-coated niobium oxide-silicon composites. Niobium oxide (Nb2O5) has various crystalline polymorphs such as pseudo-hexagonal (TT-Nb2O5), orthorhombic (T-Nb2O5), tetragonal (M-Nb2O5) and monoclinic (H-Nb2O5). These various crystalline polymorphs of Nb2O5 can be prepared by varying the heat treatment temperature, of which orthorhombic structure is favorable for fast Li ions storage. T-Nb2O5 exhibits excellent rate performance during cycling due to its Li insertion/desertion mechanism. However, T-Nb2O5 has a relatively low capacity and thus, silicon and T-Nb2O5 were combined to obtain a high capacity and stable cycle performance. In addition, to increase the electrical conductivity of both silicon and T-Nb2O5, carbon incorporation was employed. First, niobium oxide-silicon composite with micrometer-sized spherical structure was prepared by a solvothermal method. In the microsphere, nanosized Si and Nb2O5 were uniformly distributed. Then, the heat treatment was done with naphthalene at 800℃ to perform both phase transformation to T-Nb2O5 for fast Li transport and carbon coating for cycle performance and enhanced electrical conductivity. As a result, a nanometer-thick carbon layer was coated on the surface. Electrochemical test results exhibited that the synthesized electrode materials showed a high reversible capacity, excellent cycle life, and good rate performance as anode materials for Li rechargeable batteries.

One-step hydrothermal synthesis of 3D porous microspherical LiFePO4/graphene aerogel composite for lithium-ion batteries

Three-dimensional (3D) porous LiFePO4/graphene aerogel (LFP/GA) composite was successfully prepared by an in-situ hydrothermal process. In this composite, the LiFePO4 microspheres assembled by nanoparticles were embedded in a three-dimensional framework intertwined with the graphene sheets, which acts as a bridge for transfer of electron and diffusion of lithium ion. The large specific surface of the composite structure enables the increased infiltration area and utilization of the active material. The content of the graphene sheet is analyzed and is found important for the Li-storage characteristics of LiFePO4. An aerogel composite with 10% of graphene displays the best electrochemical performance, with the specific discharge capacities of 168 mAh g−1 and 155 mAh g−1 at respectively 0.1C and 1C, and the capacity retains 96.3% for up to 800 cycles. This novel 3D porous aerogel composite is identified as a promising cathode material for the rechargeable Li battery, and the simple strategy may be applied to construct other high performing composite structure and materials.

In-Plane Highly Dispersed Cu2O Nanoparticles for Seeded Lithium Deposition.

Uncontrollable dendrite growth is one of the major problems that hinders the application of lithium (Li) metal anode in rechargeable Li batteries. Achieving uniform Li deposition is the key to tackle this intractable problem. Herein, we report the highly dispersed Cu2O nanoparticles (NPs) in situ anchored on partially reduced graphene oxide via a low-temperature pyrolysis process could serve as seeds for the Li metal deposition. The lithiophilic nature of Cu2O NPs reduces the overpotential of Li nucleation and relieves the electrode polarization, enabling uniform Li nucleation and smooth plating, thus effectively eliminating dendritic and dead Li. As a result, the resulted Li metal electrodes deliver a high Coulombic efficiency of 95.6% after 140 cycles at a current density of 2 mA cm-2 and a prolonged lifespan (800 h at 1 mA cm-2) for the symmetrical cell.

Regulating Key Variables and Visualizing Lithium Dendrite Growth: An Operando X-ray Study.

Although Li metal has long been considered to be the ideal anode material for Li rechargeable batteries, our limited understanding of the complex mechanism of Li plating has hindered the widespread deployment of Li metal anodes. Therefore, operando studies are required to unambiguously reveal the complex mechanistic steps involved. In this study, we employed synchrotron-based X-ray imaging methods to visualize the evolution of Li plating/stripping under operando and, more importantly, practical conditions for battery operation, providing detailed insights into morphology evolution during Li plating. The effects of critical battery operating parameters, including concentration of Li salts, current density, ionic strength, and various electrolytes and additives, on Li plating/stripping have been studied. The delicate interplay of these conditions on the resulting Li metal morphology has been characterized for the first time.

CuCl2-Based Cathode Material with Incombustible Inorganic Liquid Electrolyte Towards Room-Temperature Na Rechargeable Battery

Na rechargeable batteries have gained much attention as an alternative power sources of Li rechargeable batteries. Nevertheless, further advance on Na rechargeable batteries is necessary, to compete in rechargeable battery market because of their low energy density and reliability. Here, we demonstrate a new type of room temperature Na rechargeable battery which employs CuCl2/C nanocomposite cathode material and SO2-based inorganic liquid electrolyte. A high discharge capacity of 200 mAh g−1 corresponding to theoretical energy density of 580 Wh kg−1 is achieved, and also a high round-trip energy efficiency (>96%) and excellent cycle-life over 1000 cycles, which has never been obtained in conventional organic electrolyte system. The remarkable electrochemical performance is mainly attributed to the use of the non-flammable SO2-based electrolyte, which guarantees a reversible conversion reaction between CuCl2 and CuCl with NaCl. Further, detailed reaction mechanism of the new battery system will be discussed in the presentation.

Stabilizing Solid Electrolyte-Anode Interface in Li-Metal Batteries by Boron Nitride-Based Nanocomposite Coating

Summary Solid-state Li-metal batteries are promising to improve both safety and energy density compared to conventional Li-ion batteries. However, various high-performance and low-cost solid electrolytes are incompatible with Li, which is indispensable for enhancing energy density. Here, we utilize a chemically inert and mechanically robust boron nitride (BN) film as the interfacial protection to preclude the reduction of Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte by Li, which is validated by in situ transmission electron microscopy. When combined with ∼1–2 μm PEO polymer electrolyte at the Li/BN interface, Li/Li symmetric cells show a cycle life of over 500 h at 0.3 mA·cm−2. In contrast, the same configuration with bare LATP dies after 81 h. The LiFePO4/LATP/BN/PEO/Li solid-state batteries show high capacity retention of 96.6% after 500 cycles. This study offers a general strategy to protect solid electrolytes that are unstable against Li and opens possibilities for adopting them in solid-state Li-metal batteries.

High‐Energy Rechargeable Metallic Lithium Battery at −70 °C Enabled by a Cosolvent Electrolyte

AbstractLithium metal is an ideal anode for high‐energy rechargeable batteries at low temperature, yet hindered by the electrochemical instability with the electrolyte. Concentrated electrolytes can improve the oxidative/reductive stability, but encounter high viscosity. Herein, a co‐solvent formulation was designed to resolve the dilemma. By adding electrochemically “inert” dichloromethane (DCM) as a diluent in concentrated ethyl acetate (EA)‐based electrolyte, the co‐solvent electrolyte demonstrated a high ionic conductivity (0.6 mS cm−1), low viscosity (0.35 Pa s), and wide range of potential window (0–4.85 V) at −70 °C. Spectral characterizations and simulations show these unique properties are associated with the co‐solvation structure, in which high‐concentration clusters of salt in the EA solvent were surrounded by mobile DCM diluent. Overall, this novel electrolyte enabled rechargeable metallic Li battery with high energy (178 Wh kg−1) and power (2877 W kg−1) at −70 °C.