Multivalent Batteries Research Articles

Iodine Boosted Fluoro-Organic Borate Electrolytes Enabling Fluent Ion-conductive Solid Electrolyte Interphase for High-Performance Magnesium Metal Batteries.

Rechargeable magnesium batteries are regarded as a promising multi-valent battery system for low-cost and sustainable energy storage applications. Boron-based magnesium salts with terminal substituent fluorinated anions (Mg[B(ORF)4]2, RF = fluorinated alkyl) have exhibited impressive electrochemical stability. Nevertheless, their deployment is hindered by the complicated synthesis routes and the surface passivation of Mganode. Herein, we report the design of an advanced electrolyte formulation comprised of B(HFIP)3and I2in 1,2-dimethoxyethane (DME), which eventually convert into a Mg[B(HFIP)4]2/DME-MgI2 electrolyte system upon interacting with Mg anode. The Mg anode reacts with I2 and the electron-accepting B(HFIP)3, leading to the in-situ formation of a solid-electrolyte interphase layer composed of MgF2 and MgI2 species that can facilitate fast and stable Mg plating/stripping. Compared with the pristine Mg[B(HFIP)4]2/DME electrolyte, the Mg[B(HFIP)4]2/DME-MgI2 electrolyte exhibited superior electrochemical performance including an ultra-low overpotential (~80 mV), high Coulombic efficiency and a long-cycling period over 1500 h. In result, the rechargeable magnesium batteries with Mg[B(HFIP)4]2/DME-MgI2 electrolyte and Mo6S8 cathode show outstanding compatibility, rapid kinetics, and stable cyclability for over 1200 cycles, surpassing all previously reported boron-based electrolytes. This work introduces a promising halogen-enhancement strategy for boron-based Mg-ion electrolytes and is pivotal for the advancement and optimization of multi-valent secondary batteries.

Dual‐Ion Co‐Insertion Engineering for Kinetics Enhancement and Stress Regulation in Cu3VS4 Toward Durable Magnesium/Lithium Hybrid Batteries

AbstractRechargeable magnesium batteries (rMBs) have tremendous development prospects in the field of energy storage, however, the strong electrostatic interactions induced by divalent Mg2+ give rise to the sluggish diffusion kinetics. Herein, the dual ion co‐intercalation strategy is proposed to expedite ion migration in Cu3VS4, achieving elevated specific capacity, transcendent rate capability, and ultra‐stable cycling capability. Kinetic analyses combined with DFT calculations indicate that the dual‐ion co‐insertion can fast charge transfer, reduce the diffusion barrier of Mg2+and optimize the reaction kinetics. Finite element simulations quantitatively verify that dual ion co‐intercalation contributes to alleviating magnesiation/lithiation‐induced stress in the shell layer and maintains structural integrity from a mechanical standpoint. Ex situ characterizations profoundly illustrates the multistep magnesium/lithium storage mechanisms and the evolution of structure. The proposed cation co‐intercalation strategy not only holds promise in opening new insights for high‐performance, continuously stable rMBs, but also provides inspiration for multivalent battery systems.

Understanding the Phase Evolution and Charging Mechanism in Dual Cation Cathodes

Multivalent batteries offer potential advantages over lithium-ion batteries but face challenges due to limited ionic mobility in solid-state cathodes. Recent investigations have demonstrated that incorporating multivalent cations, particularly calcium ions (Ca2+), into monovalent cathodes such as NaSICON and R-3m NaV2(PO4)3, results in improved capacity retention. This study investigates the phase evolution and charging mechanism in these dual cation cathodes by using a cluster expansion and charge-neutral Monte Carlo simulation in a Ca-Na-V2(PO4)3 system. Our results found that during the discharge with either Ca or Na ions, phase transitions occurs when the oxidation state of the transition metal changes, in particular between Na1V2(PO4)3 - Na3V2(PO4)3 and Na1V2(PO4)3 - Ca1V2(PO4)3. This behavior suggests that the charging pathway of Na/Ca ions can be altered by varying the Ca/Na chemical potential. Figure 1

Quantum-Chemistry Enabled AI for Materials Discovery for Energy Storage

A priori and reliable simulations can enable timely and cost-efficient design and discovery of materials for energy. Therefore, ‘Let’s Start from Computing’ is an optimal approach to initialize modern day R&D processes. In energy storage, beyond lithium-ion (BLI) research has the potential to revolutionize consumer electronics including portable and stationary power, transportation, and grid energy storage sectors. Multi-valent (Mg, Ca, Zn) energy storage or economically viable monovalent (Na, K) batteries, high-density metal-air, metal-sulfur batteries, or grid-storage systems are considered in the beyond lithium-ion research and development. All these R&D efforts require significant fundamental knowledge via a priori computations for materials discovery, property prediction, and optimization. Atomistic modeling when coupled with reliable Artificial Intelligence (AI) approaches can provide accurate insights to accelerate discovery of optimalelectrolytes, electrodes, and membranes for BLI systems to reduce the cost. Thus, coupled with AI and multi-scale simulations techniques, atomistic modeling can address prediction of molecular level properties of materials (redox potentials, solvation, spectroscopic, and reactivity) to down-select optimal materials or material combinations. In this presentation, I will describe some of our recent efforts in active learning coupled with large scale first principles simulations to down select/optimize desired molecules for flow battery technology. This concept can be utilized for design of experiments using autonomous experimentation. Additionally, I will describe some of our quantum chemistry-informed molecular property predictions redoxmers and liquid organic hydrogen carriers. In addition to molecules, I will present. A data driven approach to study longer time scale diffusion of ions for multivalent battery concepts. Figure 1

Structural and chemical evolutions of a magnesium vanadium oxide cathode under electrochemical cycling in magnesium batteries

The design of cathode materials that remain chemically and structurally stable during repetitive ion insertion and extraction poses a significant challenge in developing multivalent batteries. The cycling stability of traditional metal oxide-based cathode is challenged by sluggish diffusion of multivalent cations and parasitic reactivity at interfacial regimes, including the cathode electrolyte interphase layer (CEI). Understanding the reactions at the cathode-electrolyte interface, particularly those induced by non-stoichiometric surface layers, is a crucial design parameter for both cathode materials and electrolytes. In this study, we employed multimodal analysis, including in situ and ex situ X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) to examine the surface reactions and subsequent structural and chemical evolutions of the CEI on high voltage magnesium vanadium oxide (MgV2O4) spinel cathode during the Mg2+ insertion/extraction processes. The results revealed that the presence of non-stoichiometric surface layers in the magnesium vanadium oxide cathode drive the decomposition of bis(trifluoromethanesulfonyl)imide (TFSI-) anion, leading to the formation of the CEI layer. The CEI layer could inhibit the Mg2+ ion transfer processes. Accompanying this reactivity-driven degradation, the magnesium vanadium oxide cathode undergoes pulverization, forming clusters of nanosized particles. This process likely improves cycling ability by creating new intercalation sites and shortening the diffusion pathway for the Mg2+ cations. This study demonstrates that controlling surface stoichiometry and engineering morphological properties are critical design parameters for high performance cathodes for multivalent batteries.

From Bulk to Interface: Solvent Exchange Dynamics and Their Role in Ion Transport and the Interfacial Model of Rechargeable Magnesium Batteries.

Multivalent battery chemistries have been explored in response to the increasing demand for high-energy rechargeable batteries utilizing sustainable resources. Solvation structures of working cations have been recognized as a key component in the design of electrolytes; however, most structure-property correlations of metal ions in organic electrolytes usually build upon favorable static solvation structures, often overlooking solvent exchange dynamics. We here report the ion solvation structures and solvent exchange rates of magnesium electrolytes in various solvents by using multimodal nuclear magnetic resonance (NMR) analysis and molecular dynamics/density functional theory (MD/DFT) calculations. These magnesium solvation structures and solvent exchange dynamics are correlated to the combined effects of several physicochemical properties of the solvents. Moreover, Mg2+ transport and interfacial charge transfer efficiency are found to be closely correlated to the solvent exchange rate in the binary electrolytes where the solvent exchange is tunable by the fraction of diluent solvents. Our primary findings are (1) most battery-related solvents undergo ultraslow solvent exchange coordinating to Mg2+ (with time scales ranging from 0.5 μs to 5 ms), (2) the cation transport mechanism is a mixture of vehicular and structural diffusion even at the ultraslow exchange limit (with faster solvent exchange leading to faster cation transport), and (3) an interfacial model wherein organic-rich regions facilitate desolvation and inorganic regions promote Mg2+ transport is consistent with our NMR, electrochemistry, and cryogenic X-ray photoelectron spectroscopy (cryo-XPS) results. This observed ultraslow solvent exchange and its importance for ion transport and interfacial properties necessitate the judicious selection of solvents and informed design of electrolyte blends for multivalent electrolytes.

First-Principles and Experimental Investigation of ABO4 Zircons as Calcium Intercalation Cathodes.

Identifying next-generation batteries with multivalent ions, such as Ca2+ is an active area of research to meet the increasing demand for large-scale, renewable energy storage solutions. Despite the promise of higher energy densities with multivalent batteries, one of their main challenges is addressing the sluggish kinetics in cathodes that arise from stronger electrostatic interactions between the multivalent ion and host lattice. In this paper, zircons are theoretically and experimentally evaluated as Ca cathodes. A migration barrier as low as 113 meV is computationally found in YVO4, which is the lowest Ca2+ barrier reported to date. Low barriers are confirmed across 18 zircon compositions, which are related to the low coordination change and reduced interstitial site preference of Ca2+ along the diffusion pathway. Among the four materials (BiVO4, YVO4, EuCrO4, and YCrO4) that were synthesized, characterized, and electrochemically cycled, the highest initial capacity of 81 mA h/g and the most reversible capacity of 65 mA h/g were achieved in YVO4 and BiVO4, respectively. Despite the facile migration of multivalent ions in zircons, density functional theory predictions of the unstable, discharged structures at higher Ca2+ concentrations (Cax>0.25ABO4), the low dimensionality of the migration pathway, and the defect analysis of the B site atom can rationalize the limited intercalation observed upon electrochemical cycling.

Fast Room‐Temperature Mg‐Ion Conduction in Clay‐Like Halide Glassy Electrolytes

AbstractThe discovery of mechanically soft solid‐state materials with fast Mg‐ion conduction is crucial for the development of solid‐state magnesium batteries. In this paper, novel magnesium gallium halide compounds are reported that achieve high ionic conductivity of 0.47 mS cm−1 at room temperature. These Mg‐ion conductors obtained by ball milling Mg and Ga salts exhibit clay‐like mechanical properties, enabling intimate contact at the electrode–electrolyte interface during battery cycling. With a combination of experimental and computational analysis, this study identifies that the soft‐clay formation is induced by partial anion exchange during milling. This partial anion exchange creates undercoordinated magnesium ions in a chlorine‐rich environment, yielding fast Mg‐ion conduction. This work demonstrates the potential of clay‐like halide electrolytes for all‐solid‐state magnesium batteries, with possible further extension to other multivalent battery systems.

Potential Co2+ and Ni2+ intercalation into nickel hexacyanoferrate in aqueous media: Study of electrochemical process and multivalent batteries implications

Alternative energy storage systems to lithium-ion batteries that can reduce the dependency on such technology have attracted great interest in recent years. Besides their current limitations, multivalent batteries based on coupling a metallic anode (Mg, Zn, Ca…) with a multivalent intercalation cathode are considered as a potential option. Prussian Blue Analogues (PBAs) have shown promising multivalent intercalation capacities and have also been employed in other scientific fields like wastewater treatment, selective element extraction, and may have a potential applicability in batteries recycling. However, some controversies have recently appeared around the capacity of PBAs to incorporate multivalent cations in aqueous media. In this work, we analyze by a combinatorial approach using structural and electrochemical techniques the potential Ni2+ and Co2+ intercalation in K0.61Ni[Fe(CN)6]0.84□0.16·2·12H2O, its limitations, the role of proton intercalation and the cation released after oxidation, which differed from the intercalated during previous reduction step. The potential implications of such findings in current uses of PBAs for multivalent batteries are also discussed.

Improving rechargeable magnesium batteries through dual cation co-intercalation strategy

The development of competitive rechargeable Mg batteries is hindered by the poor mobility of divalent Mg ions in cathode host materials. In this work, we explore the dual cation co-intercalation strategy to mitigate the sluggishness of Mg2+ in model TiS2 material. The strategy involves pairing Mg2+ with Li+ or Na+ in dual-salt electrolytes in order to exploit the faster mobility of the latter with the aim to reach better electrochemical performance. A combination of experiments and theoretical calculations details the charge storage and redox mechanism of co-intercalating cationic charge carriers. Comparative evaluation reveals that the redox activity of Mg2+ can be improved significantly with the help of the dual cation co-intercalation strategy, although the ionic radius of the accompanying monovalent ion plays a critical role on the viability of the strategy. More specifically, a significantly higher Mg2+ quantity intercalates with Li+ than with Na+ in TiS2. The reason being the absence of phase transition in the former case, which enables improved Mg2+ storage. Our results highlight dual cation co-intercalation strategy as an alternative approach to improve the electrochemical performance of rechargeable Mg batteries by opening the pathway to a rich playground of advanced cathode materials for multivalent battery applications.

Generalizable, tunable control of divalent cation solvation structure via mixed anion contact ion pair formation

Multi-anion electrolytes form mixed anion contact ion pairs (CIPs), even when the constituent anions do not form CIPs in isolation. Mixed anion CIPs are shown to be general for divalent cations, and their relative fraction is tunable by composition.

(Invited) Understanding and Controlling Electrolyte Solvation-Stability Relationships Toward Energy Dense Multivalent Batteries

High energy density multivalent batteries, primarily those based on Mg or Ca metal anodes, have remained theoretically promising but practically elusive for many years. Simultaneous development of novel electrolytes and cathode materials has been undertaken across the globe in an attempt to make such batteries practical. However, a relative dearth of effective solid-electrolyte-interphase (SEI) chemistry in these systems imposes stability challenges for the electrolyte at the strongly reducing metal anode and strongly oxidizing transition metal oxide cathode interfaces. Therefore, electrolyte advances have been driven primarily by the utilization of constituents having exceptional reductive and/or oxidative stability. Addressing these intrinsic stability criteria are, however, only half the battle; the solvation interactions of these constituents with the strong Lewis acid working cations and the resultant stability effects must be considered as well.In this presentation I will describe recent insights and approaches in Mg and Ca battery electrolyte design from the solvation science perspective incorporating both theory and experiment. I will focus especially on strategies for managing solvent-cation interactions to achieve electrolyte stability toward both anodes and cathodes. From this discussion, I will provide some perspective on opportunities and considerations for future advancement in multivalent (or other) battery electrolytes.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

(Invited) Combining Constant Potential Molecular Dynamics and Experiments to Study Electrolyte Effects at Solid/Liquid Interfaces

Liquid electrolytes are at the heart of many devices in energy storage and conversion applications. Bringing an atomistic picture of the composition-properties relation is essential to understand how their reactivity can be tuned, both in the bulk and at interfaces, by variation of their composition.In this talk, I will present some recent works where we elucidated the role of the electrolyte, by using state-of-the-art constant potential classical Molecular Dynamics [1] in combination with experiments. I will first introduce some developments that we did for treating metallic surfaces within the constant potential approach, which allows computing interfacial properties, e.g. capacitance, in good agreement with experiments.[2] Then, I will show a study about the insertion process of Li+ into LiFePO4 and K+ into Prussian blue for Li-ion and K-ion batteries, in aqueous vs non-aqueous electrolytes. I will describe the molecular aspects of the electrode-electrolyte interface that dictate ion transport and insertion processes, which strongly depend on the nature of the electrolyte.[3]I will finally illustrate some exciting perspectives for the design of more complex electrolytes, where water and an organic solvent are mixed, to control the reactivity of water at a solid/liquid interface. This finds direct applications in practical devices such as Li-ion batteries, multivalent batteries, or even electrolyzers. Our strategy was to confine the reactive species, i.e. water, in a non-reactive organic matrix and different salts. Modifying the nature of the salt as well as the salt/water ratio can be used to fine tune the water reactivity at the interface by controlling its coordination environment at both short- and long-range.[4,5] References [1] A. Marin-Laflèche et al., J. Open Source Softw., 5, 2373, 2020.[2] A. Serva, L. Scalfi, B. Rotenberg, M. Salanne, J. Chem. Phys., 155, 044703, 2021.[3] P. Lemaire, A. Serva et al., ACS Appl. Mater. Interfaces, 14, 20835, 2022.[4] N. Dubouis, A. Serva et al., Nat. Catal., 3, 656, 2020.[5] A. Serva, N. Dubuois, A. Grimaud, M. Salanne, Acc. Chem. Res., 54, 1034, 2021.

Pair Distribution Function Analysis of Local Structural Rearrangement in Spinel Vanadium Oxide Cathodes

Being a divalent cation with the lowest mass, Mg2+ has garnered quite attention in recent times due to the high volumetric capacity of it’s batteries. Theoretical studies reveal that the combination of a Mg anode and a spinel oxide cathode would be able to surpass the current limits found in widely used Li-ion batteries Therefore, to design materials with high diffusion and reversible insertion capacity, a conclusive demonstration of the intercalation mechanism of Mg2+ into metal oxides, is required.Among the numerous options for cathodes, vanadium oxides show evidence of the largest capability toward reversible intercalation of Mg ions. In particular, spinel-type MgV2O4 shows a capacity of 200 mAh/g, corresponding to the cycling of ~0.7 mol Mg2+ per mol of oxide, and layered α-V2O5 reaches 300 mAhg-1, intercalating 1 mol Mg2+ per mol of oxide. The extent and reversibility of these reactions were confirmed by elemental, redox and structural characterization in recent work [1,2]. This high capacity is only observed at 110°C and it is accompanied by a large hysteresis in potential during the electrochemical cycling. The push to overcome these bottlenecks demands a more comprehensive definition of the underlying mechanisms of reaction than is currently available.Previous X-ray Diffraction (XRD) measurements conducted on the oxide indicated a loss of reflection intensity due to a loss in their crystallinity which makes structural characterization using typical diffraction techniques difficult. Through this work, we mainly make use of pair distribution function techniques to study the changes in the local structures of these oxides in both their pristine and charged state, and the effect of annealing for longer hours with the goal of further pushing the efficiency of multivalent battery materials.Reference: Hu, L., Jokisaari, J.R., Kwon, B.J., Yin, L., Kim, S., Park, H., Lapidus, S.H., Klie, R.F., Key, B., Zapol, P. and Ingram, B.J., 2020. High capacity for Mg2+ deintercalation in spinel vanadium oxide nanocrystals. ACS Energy Letters, 5(8), pp.2721-2727. Yoo, H.D., Jokisaari, J.R., Yu, Y.S., Kwon, B.J., Hu, L., Kim, S., Han, S.D., Lopez, M., Lapidus, S.H., Nolis, G.M. and Ingram, B.J., 2019. Intercalation of magnesium into a layered vanadium oxide with high capacity. ACS Energy Letters, 4(7), pp.1528-1534.

(Invited) Role of Solvent Exchange Dynamics in the Performance of Metal Anode

Designing resilient and high performing batteries is a critical component in decarbonizing our economy. Facilitating the uniform and fully reversible deposition of the metal anode remains a major roadblock in realizing many battery chemistries, including multivalent batteries. The intrinsic electrolyte properties, such as the solvation phenomena of the working cation, have widely known as critical control factor to facilitate the reversible, dendrite-free, and efficient charge transfer at metal anode. However, predominant work in this field is focused on static view of solvation phenomena, such as structure and composition of first sphere solvation shell, although the solvation process is highly dynamic and driven by solvent and/or anion exchange processes driven by thermodynamic and kinetic equilibrium conditions. In this presentation, we will discuss how exchange, conformal, and re-organizational dynamics of electrolyte constituents around divalent metal cations affects the performance metrics of metal anode based batteries, namely (1) the ionic diffusivity and emerging conductivity of the bulk electrolyte; (2) the de/re-solvation processes of metal cations and emergent overpotential; and (3) the SEI evolution and emerging interfacial impedance. Through this study, we aim to generalize the strategies for designing new electrolyte systems for high-performance batteries by recognizing and regulating the critical role of solvation dynamics of working cations.

Modulating Entropic Driving Forces to Promote Metal Ion Mobility in Ionic Liquids

Ionic liquids and organic ionic plastic crystals promise to provide safer, nonflammable alternatives to the unstable organic electrolytes currently used in commercial batteries. However, the performance of ionic liquids and organic ionic plastic crystals as battery electrolytes has been hindered by poor lithium transport, in large part due to the formation of strong lithium-anion complexes. Similar ion coordination exists in ionic liquids containing dissolved sodium, magnesium, and calcium, suggesting that design of ionic liquids for sodium and multivalent battery chemistries will face similar challenges. In this talk, I will discuss our work on the design and characterization of novel ionic liquid-inspired organic electrolytes that leverage unique self-assembly properties of molecular diamond templates, called “diamondoids,” to promote selective redox ion transport. By leveraging the unique self-assembly properties of diamondoids, we show that metal cation-anion coordination can be reduced, and possibly removed, resulting in enhanced mobility of redox-active cations. Specifically, our investigation of electrolyte phase behavior, vibrational spectra, and magnetic environments demonstrates that metal salt solubility can remain high while metal cation-anion coordination is suppressed. Our results provide a new paradigm for enhancing redox species mobility in ionic liquid-derived electrolytes by engineering cation functional groups to enhance organic cation-anion interactions, suppress metal coordination, and leverage packing mismatches to enhance redox species mobility.

Electrolyte Reactivity on the MgV2O4 Cathode Surface.

Predictive understanding of the molecular interaction of electrolyte ions and solvent molecules and their chemical reactivity on electrodes has been a major challenge but is essential for addressing instabilities and surface passivation that occur at the electrode-electrolyte interface of multivalent magnesium batteries. In this work, the isolated intrinsic reactivities of prominent chemical species present in magnesium bis(trifluoromethanesulfonimide) (Mg(TFSI)2) in diglyme (G2) electrolytes, including ionic (TFSI-, [Mg(TFSI)]+, [Mg(TFSI):G2]+, and [Mg(TFSI):2G2]+) as well as neutral molecules (G2) on a well-defined magnesium vanadate cathode (MgV2O4) surface, have been studied using a combination of first-principles calculations and multimodal spectroscopy analysis. Our calculations show that nonsolvated [Mg(TFSI)]+ is the strongest adsorbing species on the MgV2O4 surface compared with all other ions while partially solvated [Mg(TFSI):G2]+ is the most reactive species. The cleavage of C-S bonds in TFSI- to form CF3- is predicted to be the most desired pathway for all ionic species, which is followed by the cleavage of C-O bonds of G2 to yield CH3+ or OCH3- species. The strong stabilization and electron transfer between ionic electrolyte species and MgV2O4 is found to significantly favor these decomposition reactions on the surface compared with intrinsic gas-phase dissociation. Experimentally, we used state-of-the-art ion soft landing to selectively deposit mass-selected TFSI-, [Mg(TFSI):G2]+, and [Mg(TFSI):2G2]+ on a MgV2O4 thin film to form a well-defined electrolyte-MgV2O4 interface. Analysis of the soft-landed interface using X-ray photoelectron, X-ray absorption near-edge structure, electron energy-loss spectroscopies, as well as transmission electron microscopy confirmed the presence of decomposition species (e.g., MgFx, carbonates) and the higher amount of MgFx with [Mg(TFSI):G2]+ formed in the interfacial region, which corroborates the theoretical observation. Overall, these results indicate that Mg2+ desolvation results in electrolyte decomposition facilitated by surface adsorption, charge transfer, and the formation of passivating fluorides on the MgV2O4 cathode surface. This work provides the first evidence of the primary mechanisms leading to electrolyte decomposition at high-voltage oxide surfaces in multivalent batteries and suggests that the design of new, anodically stable electrolytes must target systems that facilitate cation desolvation.

Correction to: The challenges and perspectives of developing solid-state electrolytes for rechargeable multivalent battery

Correction to: The challenges and perspectives of developing solid-state electrolytes for rechargeable multivalent battery

Probe Growth and Degradation of SEI at Multivalent Battery Systems

Solid Electrolyte Interface (SEI) has not been widely reported for multivalent battery systems. Question such as whether there’s a SEI growth at the interface of the metal anode and the multivalent electrolytes is unclear. How the SEI is formed and its evolution with the electrochemical process is not known. Our lab has spent a great deal of efforts of understanding the role of SEI, its composition and evolution for multivalent electrolyte systems, and this work aims to give an overview of the recent research efforts with the use of the operando electroanalytical methods that reveal the SEI evolution for multivalent battery designs.

Investigation of Suitability of Electrolytes in a Trivalent System

As lithium-ion batteries (LIB) start to approach their theoretical limit, researchers are focusing on alternatives such as nonaqueous multivalent systems. There are many advantages of multivalent systems such as higher natural abundance, low cost and possible high volumetric capacity. Suitable electrolytes are vital for the development of such multivalent battery systems which offer compatibility of utilizing metal anode. To create a better understanding of the opportunities and challenges of the trivalent electrolytes in aluminum batteries, this work investigates the reaction mechanisms and SEI interactions at the electrolyte/electrode interface.