Aqueous Lithium-ion Batteries Research Articles

A Flexible Multifunctional Cyanoethyl-Modified Bacterial Cellulose Nanofiber Framework for High-Energy and High-Power Density Aqueous Li-Ion Batteries.

Aqueous rechargeable lithium-ion batteries (ARLIBs) are extensively researched due to their inherent safety, typical affordability, and potential high energy density. However, fabricating ARLIBs with both high energy density and power performance remains challenging. Herein, based on cyanoethyl-modified bacterial cellulose nanofibers (CBCNs), a multifunctional fast ion transport framework is developed to construct the flexible free-standing ARLIBs with high areal loading and excellent rate performance. Benefiting from the unique merits of CBCNs, such as ultra-high aspect ratio, excellent toughness, superior adhesion, good lithiophilicity and ideal stability, the flexible free-standing and highly robust electrodes are fabricated and exhibit a long-term stable cycling of 1200 cycles with a high specific capacity of 117 mAh∙g-1 at 15 C. Remarkably, the corresponding full cell with the free-standing high mass loading (45.5 mg∙cm-2) electrodes under the condition of ultra-low addition of battery binder demonstrates a cycle lifespan of over 1000 cycles with a specific capacity of 120 mAh∙g-1 and a capacity decay as low as 0.03% per cycle, which is far superior to those of almost all previous reports. This work provides a strategy for constructing ARLIBs with high energy density and power performance by introducing a unique fast ion transport nanofiber framework.

Superior electrochemical performances of Lithium vanadium oxide with coconut shell-based porous carbon as the anode of the aqueous Li ion battery

Carbon materials, as the skeleton structure of electrode materials, are composited with lithium-ion anode materials, which not only increase the electrical conductivity of the materials, but also enhance the electrochemical performance of the electrode materials. In this paper, LiV3O8@C composites were prepared by using coconut shell-based porous carbon to structurally modulate aqueous lithium-ion anode materials. And three composites with different structures and sizes were successfully synthesized by hydrothermal method, hydrothermal stirring method and improved solid-phase method. After XRD and SEM analyses, it was found that all three composites maintained the monoclinic crystal system structure of LiV3O8, and the materials prepared by the hydrothermal method showed a smooth layer structure, while the materials prepared by the hydrothermal stirring method and the solid-phase method showed nanorods with different sizes. The prepared anode materials and LiFePO4 cathode materials were assembled into an aqueous lithium-ion full battery, and were subjected to charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that the electrochemical performances of the three composites are significantly improved compared with the pure LiV3O8. Specifically, the discharge capacities of the two groups of nanorod-like composites were 112.2 mAh/g and 85.5 mAh/g at a rate of 0.2 C, which were improved by as much as two times compared with the pure LiV3O8. However, the composite material with layered structure not only reaches an initial discharge specific capacity of 148.39 mAh/g, which is 2.7 times higher than that of the pure LiV3O8, but also effectively slows down the dissolution effect of LiV3O8 by compositing with the carbon material, and at the same time, it shows excellent rate performance.

Aqueous lithium-ion battery of dual electrolytes separated by cation-exchange membrane with enhanced rate capability for thick electrodes

Aqueous lithium-ion batteries (ALIBs) have received increasing attention because of their high safety. An aqueous electrolyte system compatible with a wider electrochemical window and high ionic conductivity is desired to increase the industrial potential of ALIBs. In this study, a dual-electrolyte system separated by a perfluorosulfonated cation-exchange membrane (CEM) was designed to demonstrate a 2 V-class ALIB. The specific compositions of the cathode and anode electrolytes to be stable in facing via the CEM were experimentally determined, where each electrolyte pH was adjusted for the lithiation/delithiation of LiMn2O4 and TiO2, together with a high ionic conductivity of >70 mS/cm. The pH difference successfully suppressed water splitting, which enabled stable battery operation in the 1.5–2.8 V range with >99 % Coulombic efficiency. The optimized cathode and anode electrolytes also exhibited better rate performances even in a thick electrode layer over 50 mg/cm2 of the active material loading than a conventional concentrated electrolyte of 21 mol/kg LiTFSI (9 mS/cm). The present system, which employs the aqueous electrolytes with smaller lithium salts and favorable ionic conductivities should increase the industrial potential of low-cost aqueous lithium-ion batteries.

Aqueous Lithium-Ion Battery with Dual Electrolytes at Equilibrium across Cation-Exchange Membrane Separator

Aqueous lithium-ion batteries (ALIBs) have been investigated as a promising safe and low-cost storage device for sustainable energy. For the stability of ALIBs, it is important to expand the electrochemical stability window of aqueous electrolytes. Although “Water-in-salt” electrolytes [1] containing significant amounts of lithium salts have been reported as an effective approach, cost reduction of the aqueous electrolyte remains a major challenge for the industrialization of such ALIBs.Controlling the pH of the aqueous electrolyte is another approach to widen the electrochemical window with a smaller use of lithium salts. The 2 V-class ALIB of Zn-coated Li4Ti5O12/LiMn2O4 was demonstrated using dual aqueous electrolytes having different pH separated by a lithium-ion conductive inorganic solid electrolyte.[2] However, lithium-ion conductive inorganic solid electrolytes may often be unstable in alkaline solutions. A perfluorinated sulfonic acid cation-exchange membrane (CEM) is one of the possible alternatives for separating two different aqueous electrolytes. In principle, the concentration of the entire electrolyte does not change during lithium-ion battery operation where lithium ions shuttle between the cathode and anode. Therefore, the specific compositions of the cathode and anode electrolytes are selected to achieve the Donnan equilibrium across the CEM, and stable battery operation is expected as long as the electrolyte equilibrium is maintained. In this study, the feasibility of this concept was investigated using ALIB cell of the anatase-TiO2/spinel-LiMn2O4.A stable combination of cathode and anode electrolytes was investigated experimentally. Several compositions of cathode and anode electrolytes were prepared, and equal volumes of the cathode and anode electrolytes were faced across the CEM, stored for 10 days at room temperature, and the composition of each electrolyte were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). After repeating this procedure, a stable combination of cathode and anode electrolytes was found as 27 g/L of Li and 8 g/L of K for an anode electrolyte, and 24 g/L of Li, 36 g/L of K, 41 g/L of P, and 68 g/L of S for a cathode electrolyte prepared using LiOH, KOH, Li2SO4, and KH2PO4. The pH was 4 and 11 for the cathode and anode electrolytes, respectively.The battery test was demonstrated for the TiO2/LiMn2O4 cells assembled with the cathode/anode electrolyte and the same 2 mol/kg Li2SO4 electrolyte in both sides for comparison. The initial charge/discharge profiles are shown in Fig. 1. The profiles were obtained by constant current of 15 mA/g regarding the weight of the cathode active material with the cutoff voltage of 2.8 V and 1.5 V in charge and discharge processes, respectively. The Coulombic efficiency was reached to 96% in the cells with electrolytes having the pH difference, whereas it was 69% in the cell with the 2 mol/kg Li2SO4. The alkaline anode electrolyte suppressed hydrogen generation sufficiently for the lithiation/delithiation of anatase TiO2, which leads to an excellent reversibility over 2 V operation with an improvement in the Coulombic efficiency of the cell with dual aqueous electrolytes.To further investigate the stability of the aqueous battery, a cycle test was conducted on the cell with the dual electrolytes. Figure 1(b) shows the discharge capacity during 100 charge-discharge cycles obtained by the constant current of 75 mA/g-cathode. The Coulombic efficiency reached >99%, and the capacity retention was calculated to be 75% at 100 cycles, which indicates that the suitable pH of the cathode and anode electrolyte was maintained during repeated charge/discharge cycles.In the presentation, we will discuss the details of the battery operation, including a role of perfluorosulfonated CEM and issues to improve the battery performance.

Computational and Experimental Study of a Sustainable Lithium Acetate and Urea-Based Electrolyte for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are the most widely used energy storage systems in portable devices, electric vehicles, large-scale energy storage power, and other applications. The optimal performance and safety of LIBs are mainly determined by the electrolyte, which facilitates the transport of Li+ ions and promotes the formation of the SEI layer. Since commercial LIBs are predominantly composed of organic-based electrolytes, these present elevated costs, safety risks, and environmental hazards due to their elevated flammability and fluorinated composition. To address these concerns, aqueous electrolytes have been explored as safer alternatives to organic solvents. However, the use of aqueous LIB electrolytes is restricted due to the narrow electrochemical stability window of water (ESWH2O ≈ 1.23 V). This problem is usually overcomed by using superconcentrated electrolytes, including "water-in-salt" and "water-in-bisalt," which extend the ESW. However, their practicality remains uncertain due to the high concentration of fluorinated salts, which leads to increased cost and toxicity.1 In this study, we employed computational and experimental methods to investigate the use of non-fluorinated aqueous electrolytes prepared by combining different ratios of LiCH3COOH and a water-urea mixture of fixed composition (LiCH3COO-H2O-CO(NH2)2) for their use as an electrolyte for LIBs. ESWs were determined by cyclic voltammetry using GCE, Pt, and Al as working electrodes. The electrolyte with the highest ESW (3.2 V) was probed to be compatible with commercial electrodes such as TiO2, LTO, LMO, and LFP, and was used to assemble a LIB cell with LTO and LMO as electrodes. This cell presented an average output voltage of 2.3 V and a specific capacity of 105 mAh/g over 200 cycles at a current density of 0.5 A/g. Furthermore, the thermodynamic and kinetic factors associated with the electrochemical stability of the electrolyte have been studied using DFT and molecular dynamics (MD), respectively. Adiabatic redox potentials of the electrolyte species obtained by DFT show calculated ESWs higher than 4.5 V. Transport properties of the species in the electrolyte were studied via molecular dynamics and these show that the diffusion of Li+ is comparable to the diffusion observed in organic electrolytes.2 Structurally, we also observed that urea disrupts the Li-water structure, leading to a decrease in the coordination number of water molecules to Li+ (CNLi-H2O = 1.4). This result has been experimentally confirmed using NIR and Raman spectroscopy. Overall, these results demonstrate the effectiveness of employing a lithium acetate-urea-based aqueous electrolyte as an alternative to organic electrolytes for the development of more secure, environmentally friendly, and sustainable LIBs.1. Brown, J.; Grimaud, A. With Only a Grain of Salt. Nat. Energy 2022, 7 (2), 126–127.2. Galvez-Aranda, D. E.; Seminario, J. M. Ion Pairing, Clustering and Transport in a LiFSI-TMP Electrolyte as Functions of Salt Concentration Using Molecular Dynamics Simulations. J. Electrochem. Soc. 2021, 168 (4), 040511.

Thermodynamically spontaneously intercalated H3O+ enables LiMn2O4 with enhanced proton tolerance in aqueous batteries

LiMn2O4 (LMO) is an attractive positive electrode material for aqueous lithium-ion batteries (ALIBs), but its inferior cycle performance limits the practical application. The degradation mechanism of LMO in ALIBs is still unclear, resulting in inability to predictably improve its structural stability. The electrode/electrolyte interface is believed to play an important role in electrode degradation. However, the interactions of the water-containing electrode/electrolyte interface of LMO are underexplored. In this work, we demonstrate the insertion of H3O+ into LMO during cycling in aqueous electrolyte and elucidate the paradoxical effects of H3O+. The crystal H3O+ enhances the structural stability of LMO by forming a gradient Mn4+-rich protective shell, but an excess amount of crystal H3O+ leads to poor Li+ conductivity, resulting in rapid capacity fading. Combining electrochemical analyses, structural characterizations, and first-principles calculations, we reveal the intercalation of H3O+ into LMO and its associated mechanism on the structural evolution of LMO. Furthermore, we regulate the crystal H3O+ content in LMO by modifying the hydrogen bond networks of aqueous electrolyte to restrict H2O molecule activity. This approach utilizes an appropriate amount of crystal H3O+ to enhance the structural stability of LMO while maintaining sufficient Li+ diffusion.

The study of electrochemical stabilization mechanism of Pt, GC, SS304, Ti and Cu as current collectors for aqueous lithium-ion batteries by electrochemical approaches

This paper employs electrochemical methods (linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS)) to investigate the electrochemical behavior of platinum, glassy carbon, 304 stainless steel, titanium, and copper in 21 and 1 M LiTFSI electrolytes. The LSV results indicate that the electrochemical stability window of the materials varies with the electrolyte concentration, and the stability window is wider in the high-concentration system. Through Tafel polarization curves and EIS analysis, the overpotential of the charge exchange process differs due to the type of material and the concentration of the electrolyte, mainly attributed to the influence of the proportion of free water, electrolyte viscosity, and SEI film formation on electrode process kinetics. After comparative analysis, glassy carbon exhibits a higher overpotential than other materials at both the cathode and anode, effectively suppressing water decomposition. These findings provide theoretical support for the development of high-performance aqueous lithium-ion battery current collector materials.

Atomic Level-Macroscopic Structure-Activity of Inhomogeneous Localized Aggregates Enabled Ultra-Low Temperature Hybrid Aqueous Batteries.

The utilization of hybrid aqueous electrolytes has significantly broadened the electrochemical and temperature ranges of aqueous batteries, such as aqueous zinc and lithium-ion batteries, but the design principles for extreme operating conditions remain poorly understood. Here, we systematically unveil the ternary interaction involving salt-water-organic co-solvents and its intricate impacts on both the atomic-level and macroscopic structural features of the hybrid electrolytes. This highlights a distinct category of micelle-like structure electrolytes featuring organic-enriched phases and nanosized aqueous electrolyte aggregates, enabled by appropriate low donor number co-solvents and amphiphilic anions. Remarkably, the electrolyte enables exceptional high solubility, accommodating up to 29.8 m zinc triflate within aqueous micelles. This configuration maintains an intra-micellar salt-in-water setup, allowing for a broad electrochemical window (up to 3.86 V), low viscosity, and state-of-the-art ultralow-temperature zinc ion conductivity (1.58 mS cm-1 at -80 °C). Building upon the unique nature of the inhomogeneous localized aggregates, this micelle-like electrolyte facilitates dendrite-free Zn plating/stripping, even at -80 °C. The assembled Zn||PANI battery showcases an impressive capacity of 71.8 mAh g-1 and an extended lifespan of over 3000 cycles at -80 °C. This study opens up a promising approach in electrolyte design that transcends conventional local atomic solvation structures, broadening the water-in-salt electrolyte concept.

Unveiling aqueous lithium-ion batteries via advanced modelling and characterisation: A review

Aqueous lithium-ion batteries (ALIBs) are promising candidates for sustainable energy storage, offering great advantages in safety, cost, and environmental impact over the conventional nonaqueous LIBs. This paper delves into the forefront of ALIB research in electrolyte formulations, electrode materials, and design strategies of ALIBs that have stemmed from the integration of advanced modelling and characterisation techniques. A detailed examination of multiscale modelling approaches, e.g., density functional theory (DFT), molecular dynamics (MD), microscopic and spectroscopic techniques, e.g., X-ray, Raman, and particularly in situ and in operando methods that provide real-time observations of battery processes, is carried out. We note that the synergy between modelling and characterisation techniques have offered unprecedented insights into the fundamental processes governing ALIB performance, however, more methods that have been demonstrated effective in commercial LIBs, can be employed and contribute to resolving the current bottlenecks of ALIBs. The models at mesoscale, continuum-scale and even larger scales can supplement DFT and MD to investigate the electrochemical processes in electrode-electrolyte interface, bulk electrolyte, porous electrodes, and prototype cells, and cooperate with essential measurements to characterise physicochemical properties of aqueous electrolytes, which are not widely discussed. Other microscopic, structural, and multi-physical characterisations, such as scanning transmission electron microscopy, computed tomography, thermography, and acoustic techniques can provide more insights into lithium intercalation, phase change and degradation, inspiring the theory and model development of ALIBs. By amalgamating the current state-of-the-art and existing challenges, this paper paves the way for future prospects in ALIBs.

Order-disorder structural engineering of vanadium oxide anode: Balancing ionic and electronic dynamic for fast-charging aqueous Li-ion battery

Fast-charging aqueous lithium-ion batteries (ALIBs) are considered as promising energy storage devices because of their non-flammability and environmentally friendly characteristics. However, how to balance the ionic and electronic dynamics for fast charging reactions remains a significant challenge under the current research status. Here, the order-disorder structural engineering strategy is adopted to resolve this issue, considering the difference between ion and electron transportation in the crystalline and amorphous phases, respectively. Vanadium oxide anodes were developed with optimized ionic and electronic dynamics by using an organic-inorganic hybrid material as a precursor along with refined regulation on the calcination temperature and time. This facile and large-scale extendable approach harnesses the benefits of the order-disorder structure to optimize Li+ storage efficiency and facilitate the high reversibility of Li-ion during fast charging. Consequently, the order-disorder V2O5-based full cell with LiMn2O4 as a cathode exhibits high specific capacity (262.71 mAh g−1, 89.35 % of the theoretical capacity of V2O5), high energy density (166.04 Wh kg−1), fast Li-ion diffusion coefficient (7.34×10−5 cm2 s−1) and fast-charging performance (only 6 min achieves 82.84 % of initial state-of-charge capacity). This work explores the ionic and electronic dynamic of ordered-disorder structure and offers new insights into the development of fast-charging metal ion batteries.

High-voltage and long-life aqueous lithium-ion batteries based on polyanionic framework structured Na3V2(PO4)3 and NbOPO4 in novel deep eutectic solvents

High-voltage and long-life aqueous lithium-ion batteries based on polyanionic framework structured Na3V2(PO4)3 and NbOPO4 in novel deep eutectic solvents

Synthesis and electrochemical studies of 1,1’-binaphthyl-2,2’-diol for aqueous rechargeable lithium-ion battery applications

The constant increase in the utilization of lithium-ion batteries (LIBs) in various field applications, including electrical vehicles and electronic devices, has led researchers to focus on their multiple path developments to obtain new electrode materials. The practical development of these electrode materials, based on organic and inorganic moieties, is challenging for various groups of LIB scientists. The concept of organic electrode materials is highly competitive with inorganic electrode materials because of the accessibility of more active sites with structural diversity, high energy and power density, environmental friendliness potential sustainability, and low cost. Herein, 1,1’-binaphthyl-2,2’-diol (BINOL) is investigated as an organic electrode material that contains two hydroxyl groups that act as active centers. The oxidative coupling process is employed to synthesize BINOL and so obtained product was characterized by using FT-IR, 1H-NMR and MASS techniques. The electrochemical investigations were carried out using sat. Li2SO4 electrolytic medium at three-electrode cell system. The Cyclic voltammetry (CV) has provided information on the anodic behavior of the material and its stability studied at different scan rates. The battery performance of the cell BINOL | Sat. Li2SO4 | LiMn2O4 by galvanostatic charge-discharge potential limit (GCPL) shows 197/171mAhg−1 specific capacity and 90% columbic efficiency. The electrochemical kinetic obtained by potentiostatic electrochemical impedance spectroscopy (PEIS) shows a semi-infinite diffusion process.

Constructing a Robust Cathode Electrolyte Interface for Aqueous Hybrid Lithium-Ion Batteries Via Regulating the Solvent–Solute Interaction in a Locally Concentrated Electrolyte

Constructing a Robust Cathode Electrolyte Interface for Aqueous Hybrid Lithium-Ion Batteries Via Regulating the Solvent–Solute Interaction in a Locally Concentrated Electrolyte

Synergistic dual co-solvents hybrid electrolyte design enabling high-voltage flexible aqueous lithium-ion fiber batteries

Flexible aqueous lithium-ion batteries are promising safe power sources for next-generation of portable and wearable electronic devices due to their intrinsic safety and eco-friendliness. However, water-related side reactions in aqueous electrolytes have greatly limited their operating voltage and electrochemical performance. Herein, we report a new family of 2.4 V high-voltage flexible aqueous lithium-ion fiber battery by designing a fluorine-free and high-voltage synergistic dual co-solvents aqueous hybrid electrolyte with high ionic conductivity, low cost, and high safety. Sulfolane and trimethyl phosphate are used as synergistic dual co-solvents, which can not only extend the electrochemical stability window of electrolyte to 3.3 V by suppressing the activity of water, but also form a S-/P-containing inorganics-rich solid electrolyte chlorination interphase for better electrochemical performance. Combined with novel flexible hybrid fiber electrodes, the resulting flexible aqueous fiber batteries exhibit high working voltage plateau (2.4 V, much higher than most reported flexible aqueous batteries), high energy density (146.5 Wh kg−1), and superior cycling performance (500 cycles). In addition, these aqueous fiber batteries present impressive mechanical flexibility, which can be easily woven into clothes to power wearable electronics. This work is an inspiration for the design of next-generation of flexible batteries with both high energy and safety.

Exploring the electrochemistry of PTCDI for aqueous lithium-ion batteries

Aqueous lithium-ion batteries (ALIBs) hold promise of providing cost-effective and safe energy storage in the context of an increasingly environmentally aware narrative. Moreover, mitigating concerns surrounding the critical raw materials present in traditional LIBs reinforces the alignment with such ideals. Herein, we delve into the electrochemistry of perylene-3,4,9,10-tetracarboxylic acid diimide (PTCDI) and evaluate its potential as an organic anode active material for ALIBs. We find the all-organic anode to reversibly (de)intercalate Li+ with moderately concentrated aqueous electrolytes, although in a slightly different manner compared with organic solvents. Furthermore, the half-cell electrochemical performance in terms of capacity, capacity retention, rate performance, Coulombic efficiency, and self-discharge, is all indeed satisfactory, where proof-of-concept ALIBs using the high voltage lithium manganese oxide (LMO) exhibit >70 Wh kg−1(PTCDI+LMO) and an average voltage of ca. 1.5 V. These findings have the intention to further encourage organic redox-active material R&D with more dilute aqueous electrolytes, potentially paving the way towards a greener and more sustainable energy landscape.

Fine Tuning Water States in Hydrogels for High Voltage Aqueous Batteries.

Hydrogels are widely used as quasi-solid-state electrolytes in aqueous batteries. However, they are not applicable in high-voltage batteries because the hydrogen evolution reaction cannot be effectively suppressed even when water is incorporated into the polymer network. Herein, by profoundly investigating the states of water molecules in hydrogels, we designed supramolecular hydrogel electrolytes featuring much more nonfreezable bound water and much less free water than that found in conventional hydrogels. Specifically, two strategies are developed to achieve this goal. One strategy is adopting monomers with a variety of hydrophilic groups to enhance the hydrophilicity of polymer chains. The other strategy is incorporating zwitterionic polymers or polymers with counterions as superhydrophilic units. In particular, the nonfreezable bound water content increased from 0.129 in the conventional hydrogel to >0.4 mg mg-1 in the fabricated hydrogels, while the free water content decreased from 1.232 to ∼0.15 mg mg-1. As a result, a wide electrochemical stability window of up to 3.25 V was obtained with the fabricated hydrogels with low concentrations of incorporated salts and enhanced hydrophilic groups or superhydrophilic groups. The ionic conductivities achieved with our developed hydrogel electrolytes were much higher than those in the conventional highly concentrated salt electrolytes, and their cost is also much lower. The designed supramolecular hydrogel electrolytes endowed an aqueous K-ion battery (AKIB) system with a high voltage plateau of 1.9 V and contributed to steady cycling of the AKIB for over 3000 cycles. The developed supramolecular hydrogel electrolytes are also applicable to other batteries, such as aqueous lithium-ion batteries, hybrid sodium-ion batteries, and multivalent-ion aqueous batteries, and can achieve high voltage output.

Distinct roles: Co-solvent and additive synergy for expansive electrochemical range and low-temperature aqueous batteries

The present study addresses the challenges encountered by aqueous lithium-ion batteries (ALiBs), specifically the limited electrochemical stability window and inadequate low-temperature energy retention. We propose a binary solvent electrolyte system comprising N,N-Dimethylformamide (DMF) as a co-solvent and 3-sulfolene (3SF) as an additive (5 wt.% 3SF in 9 M LiTFSI H2O/DMF with a molar ratio of 1:1). The H2O solvent ensures non-flammability and high safety, while DMF reduces the freezing point and enhances low-temperature conductivity. Additionally, DMF actively solvates Li+ ions, thereby reducing interfacial H2O content. Moreover, through the incorporation of the 3SF additive along with LiTFSI, a stable bilayer interphase film is formed on the anode surface effectively expanding the electrochemical stability window to 4.37 V. By leveraging the distinct roles played by solvents and additive, exceptional performance at both room temperature and low-temperature is achieved for the LiMn2O4/Li4Ti5O12 cell. Specifically, at room temperature, the cell demonstrates an initial coulombic efficiency reaching 90 %. Moreover, even after undergoing 300 cycles at 1 C, the capacity remains as high as 156.3 mAh g−1 (with a remarkable capacity retention rate of 96 %). Notably, in extremely low-temperatures of -30 °C, the cell exhibits excellent cycling performance which can still maintain a capacity retention rate of 98.8 % after 50 cycles. The proposed electrolyte design strategy, which takes into account both the bulk electrolyte and interfacial chemistry, presents a practical and feasible approach for the development of safe, low-temperature, and high-energy density ALiBs.

A Green Asymmetric Bicyclic Co-Solvent Molecule for High-Voltage Aqueous Lithium-Ion Batteries.

Hybridizing aqueous electrolytes with organic co-solvents can effectively expand the voltage window of aqueous electrolytes while reducing salt usage, but most reported co-solvents are usually flammable and toxic, hardly achieving compatibility between safety and electrochemical performance. Here, a new non-flammable and non-toxic low-salt-concentration (1.85 m) aqueous electrolyte is reported using the green co-solvent isosorbide dimethyl ether (IDE). Owing to its unique 3D molecular structure, IDE can form a five-membered ring structure by binding the Li ion. The steric hindrance effect from IDE weakens its solvation ability, generating anion-participated solvation structures that produce a robust and uniform LiF-rich solid electrolyte interphase layer while containing elastic IDE-derived organics. Moreover, the multiple O atoms in IDE can effectively regulate the intermolecular hydrogen bonding networks, reducing H2O molecule activity and expanding the electrochemical window. Such unique solvation structures and optimized hydrogen bonding networks enabled by IDE effectively suppress electrode/electrolyte interfacial side reactions, achieving a 4.3 V voltage window. The as-developed Li4Ti5O12(LTO)||LiMn2O4(LMO) full cell delivers outstanding cycling performance over 450 cycles at 2 C. The proposed green hybrid aqueous electrolyte provides a new pathway for developing high-voltage aqueous lithium batteries.

A nanoengineered vanadium oxide composite as a high-performance anode for aqueous Li-ion hybrid batteries.

Aqueous lithium-ion batteries (LIBs) have received increasing attention as a promising solution for stationary energy storage systems due to their low environmental impact, non-flammability and low cost. Despite recent progress in electrolyte development and cathode manufacturing, the lack of anode materials with high specific capacity presents difficult challenges for a wide range of applications. In this study, we propose a novel synthetic strategy to fabricate a pseudocapacitive V2O5/graphene composite as a highly functional anode material for aqueous LIBs. The designed synthesis combines a fast laser-scribing step with controlled calcination to tune the morphology and oxidation state of the electrochemically active vanadium oxide species while obtaining a highly conductive graphene scaffold. The optimized V2O5/graphene anode shows an outstanding specific capacity of 158 mA h g-1 in three-electrode measurements. When the V2O5/graphene anode is paired with an LiMn2O4 cathode, the charge storage mechanism of the full cell is revealed to be dominantly surface-controlled, resulting in remarkable rate performance. Specifically, the full cell can reach a specific capacity of 151 and 107 mA h (g anode)-1 at C/6 and 3C, respectively. Moreover, this hybrid battery can achieve a high power density and an energy density of 650 W kg-1 at 15.6 W h kg-1 and 81.5 W h kg-1 at 13.6 W kg-1, respectively, outperforming most aqueous LIBs reported in the literature. This innovative strategy provides a pathway to incorporate pseudocapacitive electrodes for improving aqueous lithium-ion storage systems, enabling safe operation of large-scale energy storage without compromising their electrochemical performance.

Layered titanium phosphate nanosheets with water in salt electrolyte toward high-voltage aqueous full lithium-ion batteries

A high voltage aqueous full lithium-ion battery using novel Ti(HPO4)2·H2O as the anode material with excellent stability.