Desolvation Kinetics Research Articles

Dual‐Doped Graphene Quantum Dots to Promote Long‐Life Aqueous Zn‐ion Batteries

ABSTRACTAs the next generation of advanced energy storage devices, aqueous Zn ions batteries (AZIBs) still face many challenges, especially dendrites on the Zn metal anode and side reactions. Although an interface modification strategy has been applied to optimize the stability of Zn metal anodes and has shown some improvement, they are still far from meeting the requirements for practical applications. There is a lack of consideration for designing a multifunctional solid electrolyte interphase (SEI) which modifies the solvation/desolvation structure of Zn ion at the interface of Zn metal anodes. Herein, we constructed an amphiphilic SEI with hydrophilic and hydrophobic properties: N, S dual‐doped graphene quantum dots (GQDs). The N, S dual‐doped GQDs have been synthesized using a one‐step hydrothermal approach and were utilized for Zn anode surface modification. When regulating the solvation structure of the Zn ion interface by N, S dual‐doped GQDs, it also promotes its desolvation kinetics, optimizes the interfacial behavior of Zn ion deposition to prohibit Zn dendrite growth, and suppresses side reactions in the Zn anode surface. The Zn|Zn symmetric cell has achieved a long cycle life of more than 800 h at 5 mA cm−2. The Zn|V2O5 battery has achieved an excellent performance of more than 80% capacity retention after 1400 cycles at 1 A g−1. This provides another novel and cost‐effective path for the SEI design of aqueous Zn‐ion batteries.

Targeted Docking of Localized Hydrogen Bond for Efficient and Reversible Zinc-Ion Batteries.

Hydrogen bond (HB) chemistry, a pivotal feature of aqueous zinc-ion batteries, modulates electrochemical processes through weak electrostatic interactions among water molecules. However, significant challenges persist, including sluggish desolvation kinetics and inescapable parasitic reactions at the electrolyte-electrode interface, associated with high water activity and strong Zn2+-solvent coordination. Herein, a targeted localized HB docking mechanism is activated by the polyhydroxy hexitol-based electrolyte, optimizing Zn2+ solvation structures via dipole interaction and reconstructing interfacial HB networks through preferential parallel adsorption. By combining in situ spectroscopic characterizations with theoretical calculations, we elucidate the dynamic evolution of localized HB networks, which enhance Zn2+ deposition kinetics and homogeneity, suppress water-induced side reactions, and mitigate vanadium framework collapse. Our findings support that the targeted HB docking strategy facilitates fast interfacial ion transport kinetics and enables high reversibility, with a substantially prolonged symmetric cell lifespan exceeding 5000 h. This work markedly advances the efficient and reversible zinc-based batteries.

Targeted Docking of Localized Hydrogen Bond for Efficient and Reversible Zinc‐Ion Batteries

Hydrogen bond (HB) chemistry, a pivotal feature of aqueous zinc‐ion batteries, modulates electrochemical processes through weak electrostatic interactions among water molecules. However, significant challenges persist, including sluggish desolvation kinetics and inescapable parasitic reactions at the electrolyte‐electrode interface, associated with high water activity and strong Zn2+‐solvent coordination. Herein, a targeted localized HB docking mechanism is activated by the polyhydroxy hexitol‐based electrolyte, optimizing Zn2+ solvation structures via dipole interaction and reconstructing interfacial HB networks through preferential parallel adsorption. By combining in situ spectroscopic characterizations with theoretical calculations, we elucidate the dynamic evolution of localized HB networks, which enhance Zn2+ deposition kinetics and homogeneity, suppress water‐induced side reactions, and mitigate vanadium framework collapse. Our findings support that the targeted HB docking strategy facilitates fast interfacial ion transport kinetics and enables high reversibility, with a substantially prolonged symmetric cell lifespan exceeding 5000 h. This work markedly advances the efficient and reversible zinc‐based batteries.

Regulating Water Molecules via Bioinspired Covalent Organic Framework Membranes for Zn Metal Anodes.

The Zn metal anode in aqueous zinc-ion batteries (AZIBs) faces daunting challenges including undesired water-induced parasitic reactions and sluggish ion migration kinetics. Herein, we develop three-dimensional covalent organic framework (COF) membranes with bioinspired ion channels toward stabilized Zn anodes. These COFs, featured by zincophilic pyridine-N sites, enable effective regulation of water molecules at the anode-electrolyte interphase. Systematic experimental analysis and theoretical simulations reveal the optimized COF-320N membrane functions as ion pumps, accordingly facilitating Zn2+ transport and inhibiting direct contact between Zn anode and free water molecules. Consequently, the bio-inspired strategy achieves improved Zn2+ transference number (0.61), rapid de-solvation kinetics, and suppressed hydrogen evolution. The assembled Zn||MnO2 pouch cell integrated with COF-320N membrane exhibits favorable electrochemical performances. Such a bioinspired concept for optimizing Zn anodes opens new pathways in developing advanced energy storage devices.

Sub‐Nano Confinement Engineering Toward Anion‐Reinforced Solvation Structure to Achieve Highly Reversible Anode‐Free Lithium Metal Batteries

AbstractThe practical application of anode‐free lithium metal batteries (AFLMBs) is impeded by poor cycling performance due to sluggish Li+ transport kinetics, unfavorable side reactions, and dendrite Li growth. To address these issues, ≈200 nm zeolitic imidazolate framework‐8 (ZIF‐8) interphase layer is introduced to enable highly reversible Li plating/stripping by electrosynthesis method. ZIF‐8 interphase layer with sub‐nano windows accelerates Li+ desolvation kinetics and thus suppresses unfavorable side reactions. Further, the internal cavities of ZIF‐8 serve as an anion reservoir to modulate anion‐reinforced solvation structure of Li+, facilitating the formation of LiF‐ and Li3N‐riched solid–electrolyte interphase. Thus, the Li/Cu@ZIF‐8 asymmetric cell exhibits remarkable Aurbach coulombic efficiency of 99.84%, and Cu@ZIF‐8/LiFePO4 AFLMB delivers impressive capacity retention (57.8%) over 400 cycles. This work highlights the effectiveness of ZIF‐8 to enable highly reversible AFLMBs and inspires the potential application of porous materials with sub‐nano windows and interval cavities in anode‐free batteries.

Tuning interfacial desolvation kinetics to stabilize ammonium vanadate cathodes in aqueous zinc-ion batteries

Tuning interfacial desolvation kinetics to stabilize ammonium vanadate cathodes in aqueous zinc-ion batteries

Low-Temperature Lithium Metal Batteries Achieved by Synergistically Enhanced Screening Li+ Desolvation Kinetics.

Lithium metal anode is desired by high capacity and low potential toward higher energy density than commercial graphite anode. However, the low-temperature Li metal batteries suffer from dendrite formation and dead Li resulting from uneven Li behaviors of flux with huge desolvation/diffusion barriers, thus leading to shortlifespan and safety concern. Herein, differing from electrolyte engineering, a strategy of delocalizing electrons with generating rich active sites to regulate Li+ desolvation/diffusion behaviors are demonstrated via decorating polar chemical groups on porous metal-organic frameworks (MOFs). As comprehensively indicated by theoretical simulations, electrochemical analysis, in situ spectroscopies, electron microscope, and time-of-flight secondary-ion mass spectrometry, the sieving kinetics of desolvation is not merely relied on pore size morphology but also significantly affected by the ─NH2 polar chemical groups,reducing energy barriers for realizing non-dendritic and smooth Li metal plating. Consequently, the optimal cells stabilize forlong lifespan of 2000 h and higher average Coulombic efficiency, much better than the-state-of-art reports. Under a lower negative/positive ratio of 3.3, the full cells with NH2-MIL-125 deliver a high capacity-retention of 97.0% at 0.33 C even under -20°C, showing the great potential of this kind of polar groups on boosting Li+ desolvation kinetics at room- and low-temperatures.

Enhancement of De‐Solvation Kinetics on V5O12•6H2O Cathode Through a Bi‐Functional Modification Layer for Low‐Temperature Zinc‐Ion Batteries

AbstractZinc‐ion batteries (ZIBs) show great promise for next‐generation energy storage, but their performance at low temperatures is severely hindered by sluggish desolvation kinetics at cathode‐electrolyte interface. To address this limitation, a zincophilic‐hydrophobic poly(3,4‐ethylenedioxythiophene) (PEDOT) modified layer is proposed on V5O12•6H2O cathode. Ab initio molecular dynamics simulations indicate that this modification strategy promotes Zn2⁺ adsorption and reduces the free energy for dissociating hydrated Zn2+ to form Zn2+ at the cathode‐electrolyte interface, across the temperature of 280 to 240 K. As a result, this PEDOT‐modified cathode exhibits significantly improved Zn2⁺ diffusion and desolvation kinetics, delivering superior rate performance with a remarkable capacity of 226.5 mAh g⁻¹ at 40 A g⁻¹. Notably, even at −30 °C, this cathode maintains a high capacity of 268.3 mA g⁻¹ at 0.2 A g⁻¹ and exhibits robust capacity retention (92.4%) over 1,000 cycles at 1 A g⁻¹. This approach markedly improves low‐temperature capacity retention and operational efficiency, highlighting the potential of cathode‐electrolyte interface engineering to advance zinc‐ion batteries performance in cold environments.

Weakly solvating nonaqueous electrolyte enables Zn anode with long-term stability and ultra-low overpotential

Developing nonaqueous electrolytes for zinc-ion batteries (ZIBs) is increasingly considered a promising solution to address the crucial issues associated with aqueous electrolytes, including hydrogen evolution, side reactions, and dendritic growth. However, most organic solvents tend to form a double-toothed or multi-toothed Zn-O strong coordination structure with Zn2+ through the donor O atom, which significantly impedes the de-solvation kinetics and results in an undesired overpotential during Zn deposition. A promising strategy is employing nitrogenous solvents to construct a weakly solvated structure with Zn-N coordination and simultaneously permit a high proportion of anion entry into the solvation sheath. Inspired by this, a weakly solvating nonaqueous electrolyte is designed using methylimidazole (EMI) and Zn(TFSI)2 as the solvent and salt, respectively, in which Zn(EMI)4.99(TFSI)1.01 is determined the most stable thermodynamic configuration. During the deposition process, the TFSI– anion in the solvated sheath is preferentially reduced, resulting in forming a double-layer solid electrolyte interface (SEI) that is rich in ZnF2, ZnS, and ZnNx favorable inorganic components. As expected, the designed nonaqueous electrolyte offers a long-term stable Zn plating/stripping performance over 7900 h (∼ 11 months) and an ultra-low overpotential of 20 mV. The Zn||Cu asymmetric cell exhibits an average Coulombic efficiency as high as 99.43%, providing a novel insight and avenue for promising nonaqueous electrolyte design.

Ionic Liquid Additive Mitigating Lithium Loss and Aluminum Corrosion for High-Voltage Anode-Free Lithium Metal Batteries.

Concentrated electrolytes based on lithium bis(fluorosulfonyl)imide (LiFSI) have been proposed as an effective Li-compatible electrolyte for anode-free lithium metal batteries (AFLMBs). However, these electrolytes suffer from severe aluminum corrosion at an elevated potential. To address this issue, we propose a binary ionic liquid (IL) electrolyte additive comprising the 1-methyl-1-butyl pyrrolidinium cation (Pyr14+), difluoro(oxalate)borate anion (DFOB-), and difluorophosphate (PO2F2-) anion to mitigate the Li inventory loss and Al corrosion in 4 M LiFSI/DME electrolyte simultaneously. On the anode side, the IL additive facilitates the formation of a robust Li3N- and LiF-rich solid electrolyte interphase, promoting highly reversible Li plating/stripping and uniform Li deposition. Additionally, the ILs alter the Li+ solvation structure, leading to enhanced tLi+ and rapid Li+ desolvation kinetics. Concurrently, on the cathode side, the ILs aid in the generation of dense LiF- and AlF-rich passivation films against Al corrosion. By using the IL-added electrolyte, the Cu||LiMn0.7Fe0.3PO4 cell operates stably at 4.5 V, and the Cu||NCM613 cell with a high loading of 4.0 mA h cm-2 sustains 142 cycles until 80% capacity retention. This research contributes to a deeper understanding of the IL additive mechanism at the electrode-electrolyte interfaces and offers a straightforward approach to designing practical high-voltage AFLMB electrolytes.

Strengthen Water O-H Bond in Electrolytes for Enhanced Reversibility and Safety in Aqueous Aluminum Ion Batteries.

Aqueous aluminum-ion batteries present a promising prospect for large-scale energy storage applications, owing to the abundance, inherent safety, and the high theoretical capacity of aluminum. However, their voltage output and energy density are significantly hindered by challenges such as complex hydrogen evolution and uncontrollable solvation reactions. In this work, we demonstrate that water decomposition is restrain by increasing the electron density of water protons and increasing the dissociation energy of H2O through robust dipole interactions with highly polar dimethylformamide (DMF) molecules. Moreover, the incorporation of dimethyl methylphosphonate (DMMP) flame retardant effectively addresses the flammability risk arising from a substantial presence of organic additives The in-depth study with experimental and theoretical simulations reveals that the water-poor solvation structure with reduced water activity is achieved, which can (i) effectively mitigate undesired solvated H2O-mediated side reactions on the Al anode; (ii) boost the de-solvation kinetics of Al3+ while preventing cathode structural distortion; (iii) reduce the flammability of hybrid electrolytes. As a proof of concept, the Al//AlxMnO2 full cell employing a hybrid electrolyte demonstrate enhanced stability (deliver 335 mAh g-1 while retaining 71 % capacity for 400 cycles) compared to those with pure electrolyte.

Electrolyte Reconfiguration by Cation/Anion Cross-coordination for Highly Reversible and Facile Sodium Storage.

Hard carbon (HC) materials are promising anodes for sodium-ion batteries (SIBs) owing to low cost, high specific capacity and low working potential. However, the poor compatibility of the electrolyte with HC leads to low initial coulombic efficiency (ICE) and sluggish Na+ transport kinetics. Here, we propose an electrolyte reconfiguration strategy based on the hard and soft acid and base (HSAB) theory by introducing methyltriphenylphosphonium bromide (MTPPB). MTPPB can realize a spontaneous cross-coordination solvation structure with NaPF6 by selective affinity, synchronously optimizing the interfacial chemistry and sodium storage process. The advantages of the chemical π-π bridging of MTPP+-HC and interaction of MTPP+-PF6- contribute to preferential and oriented reduction of PF6-, forming a low-resistance supramolecular SEI. Additionally, Na+-Br- coordination weakens the Na+-solvent interactions, facilitating Na+ de-solvation kinetics. Consequently, the HC||Na cell achieves a superior ICE of 96.6%, desirable rate capability under 25 °C and invisible capacity decay after 500 cycles at 1 C under -20 °C. The Na4Fe3(PO4)2P2O7||HC pouch battery displays a high ICE of 90.3% and a 15% increment of energy density under 25 °C. This work provides a guidance through electrolyte reconfiguration engineering for designing practical HC-based SIBs with high energy/power density and long-life span in the extended operating-temperature range.

Halogenated solvation structure and preferred Zn (002) deposition via trace additive towards high reversibility for aqueous zinc-ion batteries

Tremendous progress has been achieved in cathode materials for aqueous zinc-ion batteries (AZIBs), however their practical applications are hindered by the poor cycling stability of Zn anode. Herein, amphiphilic choline bromine (ChBr) is introduced as additive into highly-concentrated ZnSO4 aqueous electrolyte, which not only regulates the traditional Zn2+ solvation structure but also establishes an electrostatic shielding layer at electrolyte-anode interface. Compared to the pristine 3 M ZnSO4 electrolyte, ChBr-modified ZnSO4 electrolyte (ZSO-ChBr) is proven effective in promoting the reversibility of zinc plating/stripping and the preferred growth of Zn (002) plane, as well as suppressing the hydrogen evolution and side reactions on Zn anode surface. As a result, Zn||Zn symmetric cell in optimal ZSO-ChBr electrolyte could harvest a remarkable lifespan over 6000 h at 5 mA cm−2 and 1 mAh cm−2, besides a highly-reversible zinc plating/stripping process over 1500 cycles was achieved in Zn||Cu asymmetric cell. Moreover, the Zn||MnO2 full cell could exhibit an excellent rate capability and the cycling stability with a capacity retention of 80 % after 400 cycles. This work provides an integrated strategy of electrolyte engineering to elevate the desolvation kinetics of Zn2+ at anode-electrolyte interface and enhance the cycling stability of Zn anode, effectively improving the electrochemical performances of aqueous zinc-ion batteries (AZIBs) and promoting the development of various energy storage systems.

Electronic effect tuned ion-dipole interactions for low-temperature electrolyte design of LiFePO4-based lithium-ion batteries

Poor low-temperature performance is one of the major challenges hindering the widespread use of lithium-ion batteries. Modulation of Li+ solvation structure to facilitate desolvation process is an important strategy in electrolyte engineering under low temperature. Herein, different electronic effect groups including electron-withdrawing groups (CH2Cl) and electron-donating groups (CH3), are introduced in the weakly solvated solvent tetrahydrofuran (THF), respectively, to compare their effects on the ion-dipole interaction in the electrolyte and thus the regulation of Li+ solvation structure. Theoretical calculations combined with characterization demonstrates that the introduction of electron-withdrawing groups CH2Cl in the solvent can reduce the electron cloud density of oxygen in the THF solvent molecule, weaken the binding energy between Li+ and the solvent, and lead to more anions participating in solvation shell of Li+ and coordinating with Li+, thus accelerating the desolvation kinetics of Li+. This electrolyte-design strategy based on electronic effect tuned ion-dipole interactions has notably increased the cycling stability of the LiFePO4||Li half-cell at –20 °C, that is, it not only increases the capacity by about 10 mAh g−1 at the rate of 0.2 C, but also maintains the capacity retention rate at 97.4 % after 100 cycles. This study reveals an important electrolyte design strategy at the molecular level.

A Microscopically Heterogeneous Colloid Electrolyte for Extremely Fast-Charging and Long-Calendar-Life Silicon-Based Lithium-Ion Batteries.

Fast-charging capability and calendar life are critical metrics in rechargeable batteries, especially in silicon-based batteries that are susceptible to sluggish Li+ desolvation kinetics and HF-induced corrosion. No existing electrolyte simultaneously tackles both these pivotal challenges. Here we report a microscopically heterogeneous covalent organic nanosheet (CON) colloid electrolyte for extremely fast-charging and long-calendar-life Si-based lithium-ion batteries. Theoretical calculations and operando Raman spectroscopy reveal the fundamental mechanism of the multiscale noncovalent interaction, which involves the mesoscopic CON attenuating the microscopic Li+-solvent coordination, thereby expediting the Li+ desolvation kinetics. This electrolyte design enables extremely fast-charging capabilities of the full cell, both at 8 C (83.1 % state of charge) and 10 C (81.3 % state of charge). Remarkably, the colloid electrolyte demonstrates record-breaking cycling performance at 10 C (capacity retention of 92.39 % after 400 cycles). Moreover, benefiting from the robust adsorption capability of mesoporous CON towards HF and water, a notable improvement is observed in the calendar life of the full cell. This study highlights the role of microscopically heterogeneous colloid electrolytes in enhancing the fast-charging capability and calendar life of Si-based Li-ion batteries. Our work offers fresh perspectives on electrolyte design with multiscale interactions, providing insightful guidance for the development of alkali-ion/metal batteries operating under harsh environments.

A Microscopically Heterogeneous Colloid Electrolyte for Extremely Fast‐Charging and Long‐Calendar‐Life Silicon‐Based Lithium‐Ion Batteries

AbstractFast‐charging capability and calendar life are critical metrics in rechargeable batteries, especially in silicon‐based batteries that are susceptible to sluggish Li+ desolvation kinetics and HF‐induced corrosion. No existing electrolyte simultaneously tackles both these pivotal challenges. Here we report a microscopically heterogeneous covalent organic nanosheet (CON) colloid electrolyte for extremely fast‐charging and long‐calendar‐life Si‐based lithium‐ion batteries. Theoretical calculations and operando Raman spectroscopy reveal the fundamental mechanism of the multiscale noncovalent interaction, which involves the mesoscopic CON attenuating the microscopic Li+‐solvent coordination, thereby expediting the Li+ desolvation kinetics. This electrolyte design enables extremely fast‐charging capabilities of the full cell, both at 8 C (83.1 % state of charge) and 10 C (81.3 % state of charge). Remarkably, the colloid electrolyte demonstrates record‐breaking cycling performance at 10 C (capacity retention of 92.39 % after 400 cycles). Moreover, benefiting from the robust adsorption capability of mesoporous CON towards HF and water, a notable improvement is observed in the calendar life of the full cell. This study highlights the role of microscopically heterogeneous colloid electrolytes in enhancing the fast‐charging capability and calendar life of Si‐based Li‐ion batteries. Our work offers fresh perspectives on electrolyte design with multiscale interactions, providing insightful guidance for the development of alkali‐ion/metal batteries operating under harsh environments.

Modulating Interfacial Zn2+ Desolvation and Transport Kinetics through Coordination Interaction toward Stable Anodes in Aqueous Zn-Ion Batteries.

Aqueous Zn-ion batteries (AZIBs) are promising candidates for grid-scale energy-storage applications, but uneven Zn2+ flux distribution and undesirable water-related interfacial side reactions seriously hinder their practical application. Herein, a strategy of regulating the coordination interaction between Zn2+ and artificial interphase layers (AILs) to modulate the interfacial Zn2+ desolvation/transport behaviors and relieve side reactions for building stable Zn anodes is proposed. By selectively choosing appropriate polymers with different functional groups, it is shown that compared with the strong interaction offered by aryl groups in polystyrene-based AILs, cyano groups in polyacrylonitrile (PAN)-based AILs provide a moderate coordination interaction with Zn2+, which not only accelerates interfacial Zn2+desolvation kinetics but also enables efficient Zn2+ transport within AILs. Moreover, the Zn2+ transport kinetics of PAN-based AILs can be further enhanced with the incorporation of an ionic conductor, zinc phosphate (ZP). Because of these advantages, the Zn anodes decorated with the hybrid AILs composed of PAN and ZP can steadily operate for >2000h at 0.2mA cm-2 and >350h at a high current density of 10mA cm-2. This work provides a valuable guideline for selective design of AILs at the molecular level for durable AZIBs.

Trace alcohol ether electrolytes with dual-site hydrogen bonds and modulated solvation structures for ultralong-life zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are highly regarded for their affordability, stability, safety, and eco-friendliness. Nevertheless, their practical application is hindered by severe side reactions and the formation of zinc (Zn) dendrites on the Zn metal anode surface. In this study, we employ tetrahydrofuran alcohol (THFA), an efficient and cost-effective alcohol ether electrolyte, to mitigate these issues and achieve ultralong-life AZIBs. Theoretical calculations and experimental findings demonstrate that THFA acts as both a hydrogen bonding donor and acceptor, effectively anchoring H2O molecules through dual-site hydrogen bonding. This mechanism restricts the activity of free water molecules. Moreover, the two oxygen (O) atoms in THFA serve as dual solvation sites, enhancing the desolvation kinetics of [Zn(H2O)6]2+ and improving the deposition dynamics of Zn2+ ions. As a result, even trace amounts of THFA significantly suppress adverse reactions and the formation of Zn dendrites, enabling highly reversible Zn metal anodes for ultralong-life AZIBs. Specifically, a Zn-based symmetric cell containing 2 % THFA achieves an ultralong cycle life of 8,800 h at 0.5 mA cm−2/0.5 mAh cm−2, while a Zn//VO2 full cell containing 2 % THFA maintains a remarkable 80.03 % capacity retention rate at 5 A g−1 over 2,000 cycles. This study presents a practical strategy to develop dendrite-free, cost-effective, and highly efficient aqueous energy storage systems by leveraging alcohol ether compounds with dual-site hydrogen bonding capabilities.

Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically‐Stable Low‐Temperature Lithium‐Ion Batteries

AbstractGraphite (Gr)‐based lithium‐ion batteries with admirable electrochemical performance below −20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+‐solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically‐stable solid electrolyte interphase (SEI) without compromising strong Li+‐solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature‐dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low‐temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e−) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4‐based, inorganics‐enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e− blocking and rapid desolvation, and as a result, much suppressed Li‐metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low‐temperature battery performances. Overall, our work originally provides visualized guides to improve low‐temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.

Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically-Stable Low-Temperature Lithium-Ion Batteries.

Graphite (Gr)-based lithium-ion batteries with admirable electrochemical performance below -20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+-solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically-stable solid electrolyte interphase (SEI) without compromising strong Li+-solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature-dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low-temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e-) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4-based, inorganics-enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e- blocking and rapid desolvation, and as a result, much suppressed Li-metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low-temperature battery performances. Overall, our work originally provides visualized guides to improve low-temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.