Cathode Electrolyte Interphase Research Articles

Dual-Salts Localized High-Concentration Electrolyte for Li- and Mn-Rich High-Voltage Cathodes in Lithium Metal Batteries.

Limited electrochemical stability windows of conventional carbonate-based electrolytes pose a challenge to support the Lithium (Li)- and manganese (Mn)-rich (LMR) high-voltage cathodes in rechargeable Li-metal batteries (LMBs). To address this issue, a novel localized high-concentration electrolyte (LHCE) composition incorporating LiPF6 and LiTFSI as dual-salts (D-LHCE), tailored for high-voltage (>4.6Vvs.Li) operation of LMR cathodes in LMBs is introduced. 7Li nuclear magnetic resonance and Raman spectroscopy revealed the characteristics of the solvation structure of D-LHCE. The addition of LiPF6 provides stable Al-current-collector passivation while the addition of LiTFSI improves the stability of D-LHCE by producing a more robust cathode-electrolyte interphase (CEI) on LMR cathode and solid-electrolyte interphase (SEI) on Li-metal anode. As a result, LMR/Li cell, using the D-LHCE, achieved 72.5% capacity retention after 300 cycles, a significant improvement compared to the conventional electrolyte (21.9% after 100 cycles). The stabilities of LMR CEI and Li-metal SEI are systematically analyzed through combined applications of electrochemical impedance spectroscopy and distribution of relaxation times techniques. The results present that D-LHCE concept represents an effective strategy for designing next-generation electrolytes for high-energy and high-voltage LMB cells.

Simultaneous structure and surface engineering of metal-organic framework derived LiNi0.5-xFe2xMn1.5-xO4 cathode material for improving high voltage performance of lithium-ion batteries

This study presents a novel material synthesis approach utilizing a terephthalic acid-based metal-organic framework as a precursor and employing an ethanol-assisted hydrothermal treatment to produce high-performance Fe-doped LiNi0.5Mn1.5O4 (LNMO) cathode material. This strategy yields a well-crystallized spinel structure with uniformly distributed transition metal ions. Additionally, the appropriate quantity of Fe dopant can achieve the desired Mn3+/Mn4+ ratio, level of structural disordering, and crystal phase purity for Fe-doped LNMO. The synthesis process also aids in forming an amorphous Li2CO3 surface layer, approximately 1 nm thick, which protects the active material from excessive reaction with electrolyte. The typical Fe-doped LNMO cathode (S-05) exhibits superior performance compared to a commercialized LNMO counterpart. It delivers an initial discharge capacity of 135 mAh g-1 at 1 C with exceptional cycling stability over 500 cycles (capacity retention of 90%) under high voltage (5.0 V vs. Li+/Li). Furthermore, its rate capability significantly improves, with a capacity retention of 85% (5 C/0.2 C). This enhanced performance aligns with evidence of activated Ni2+/Ni3+/Ni4+ redox reactions and suppressed cathode electrolyte interphase resistance, leading to promoted Li+ diffusion. Moreover, it is found the cathode helps alleviate electrolyte degradation at high voltages by inhibiting the formation of singlet oxygen in the electrolyte.

Ultrafast Tailoring Amorphous Zn0.25V2O5 with Precision-Engineered Artificial Atomic-Layer 1T'-MoS2 Cathode Electrolyte Interphase for Advanced Aqueous Zinc-Ion Batteries.

Vanadium (V)-based oxides as cathode materials for aqueous zinc-ion batteries (AZIBs) still encounter challenges such as sluggish Zn2+ diffusion kinetics and V-dissolution, thus leading to severe capacity fading and limited life span. Here, we designed an ultrafast and facile colloidal chemical synthesis strategy based on crystalline Zn0.25V2O5 (c-ZVO) to successfully prepare a-ZVO@MoS2 core@shell heterostructures, where atomic-layer MoS2 uniformly coats on the surface of amorphous a-ZVO. The tailored amorphous structure of a-ZVO provides more isotropic pathways and active sites for Zn2+, thus significantly enhancing the Zn2+ diffusion kinetics during charge-discharge processes. Meanwhile, as an efficient artificial cathode electrolyte interphase, the precision-engineered atomic-layer MoS2 with semi-metallic 1T' phase not only contributes to improved electron transport but also effectively inhibits the V-dissolution of a-ZVO. Therefore, the prepared a-ZVO@MoS2 and conceptually validated a-V2O5@MoS2 derived from commercial c-V2O5 exhibit excellent cycling stability at an ultralow current density (0.05 A g-1) while maintaining good rate capability and capacity retention. This research achievement provides a new effective strategy for various amorphous cathode designs for AZIBs with superior performance.

Revisiting ether electrolytes for high-voltage sodium-ion batteries

While ether electrolytes show great potential for anode materials of sodium-ion batteries (SIBs), they are perceived to be intolerant to high voltage (4.0 V and above) and are rarely employed in cathode materials. Herein, four typical ether electrolytes are examined and the oxidative stability is demonstrated to be closely related to their solvation structures. The anion-involved solvation structure lowers the tolerance of weakly solvated electrolyte to high voltage, and the resulting inorganics-rich cathode electrolyte interphase is equipped with high resistance and friability, leading to undesired rate and cycle performance. In contras, strongly solvated electrolytes can cycle stably at a high voltage of 4.3 V with high rate performance. As a proof-of-concept, the Graphite//Na3(VOPO4)2F full cell based on G2 electrolyte (1 M NaPF6 in glyme) can deliver a high energy density of 126.3 Wh kg−1 at 61.2 W kg−1 and a desirable power density of 5424.3 W kg−1 at 65.1 Wh kg−1, providing a demonstration for the potential application of ether electrolytes in high-voltage SIBs.

Realizing the single-crystalline LiNi0.90Mn0.05Co0.05O2 cathode with long-life and high-safety property driven by polysiloxane covering and PO43− doping

As a promising cathode for lithium-ion batteries, the ultra-high nickel content layered oxide LiNi0.90Co0.05Mn0.05O2 demonstrates the great attention for the high discharging capacity. However, the serious capacity attenuation resulted from the instable interface, crystal structure degeneration and strong side-reactions on cathode-electrolyte interphase with charging-discharging drastically restricts its extensive application. To alleviate the intrinsic drawbacks, the combination improvement strategy for polysiloxane covering and PO43− doping is adopted to lower the surface residual alkali amounts, defend the HF/F− attacking and enhance the cation location order of LiNi0.90Co0.05Mn0.05O2. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) are used to evaluate the synthesized samples. The cathodes after the polysiloxane covering and PO43− doping deliver the improved crystal structure, larger lattice parameters and superior electrochemical properties. The polysiloxane coated and PO43− doped sample exhibits a high discharging capacity of 147.5 mAh g−1 at 10.0C rate and 155.4 mAh g−1 at −30 °C, remains a capacity of 193.2 mAh g−1 at 1.0C after 300 cycles with a retention of 91.2 %. Besides, when applied in pouch full batteries, it could pass the rigorous safety tests of Bar impact, Overcharging test and Nail penetration successfully, and still maintain the superior cycling stability in practice application.

Enhancing the performance of LiNi0.8Mn0.1Co0.1O2-based pouch cells through advanced electrolyte additive systems for high-temperature lithium-ion batteries

Next-generation lithium-ion batteries, which achieve high energy densities and prolonged cycle performance, require cathode materials with high operating voltages and specific capacities. Because of their high capacity and operating voltage, nickel-rich layered oxides like LiNi0.8Mn0.1Co0.1O2 (NMC811) are attractive cathodes; nevertheless, they have drawbacks such capacity loss, poor cycle performance, structural instability, and thermal instability. Enhancing the stability of the NMC811 cathode-electrolyte interphase demands improvements in both cathode materials and electrolytes. This study explores the enhancement of NMC811-based battery systems through electrolyte modification, focusing on mixed additive combinations to evaluate their synergistic effects at elevated temperatures, relevant for tropical climates. A ternary additive system comprising vinylene carbonate (VC), lithium difluorophosphate (LiPO2F2), and p-toluenesulfonyl isocyanate (PTSI) in a LiPF6-based electrolyte showed significant improvements. This system mitigated capacity fading for cells cycled over 3 V–4.2 V at both 25 °C and 45 °C, outperforming the baseline electrolyte. The designed electrolyte stabilized the electrode-electrolyte interface, enhancing cell performance and the cathode's structural integrity. Notably, the graphite/NMC811 pouch cell's cycling performance showed an increase in capacity retention from 82.4% to 90.2% after 150 cycles at C/2 at 45 °C. Moreover, the deactivation of PF5 by PTSI can help to suppress the side reaction from the instability of LiPF6-based electrolytes, especially at elevated temperatures. These findings carried out from this strategic electrolyte additive system can substantially improve nickel-rich LIBs, especially in challenging thermal environments.

Formation of a Cathode Electrolyte Interphase on High-Voltage Li-ion Cathodes

Formation of a Cathode Electrolyte Interphase on High-Voltage Li-ion Cathodes

Assessment of “Inverse” Cross‐Talk (Anode to Cathode) in High‐Voltage Li/Mn‐Rich Layered Oxide || Li Cells

AbstractLi/Mn‐rich layered oxide (LMR) offers high practical discharge capacity originating from both cationic and anionic redox, but its operation is practically challenging as full capacity utilization at high cathode potentials (> 4.6 V vs Li|Li+) is intertwined with phase transformation, oxygen release, and transition metal dissolution. Dissolved TMs in particular, can deposit and damage the anode via a process known as electrode cross‐talk that decreases Li inventory due to Li plating. Given the excess in active lithium, Li‐metal anode (LMA) is frequently paired with LMR for a systematic cathode R&D, though is believed to cause inverse cross‐talk, i.e., diffusion of LMA degradation products from the solid electrolyte interphase (SEI) toward the cathode, triggering bulid‐up of resistive cathode electrolyte interphase (CEI). Indeed, a thicker, more organic‐based, and slightly resistive CEI is proven in Li‐ compared to “SEI‐poor” Li4Ti5O12 (LTO)‐based cells via X‐ray photoelectron spectroscopy, time‐of‐flight secondary ion mass spectrometry, and electrochemical techniques, which likely even decreases metal dissolution from LMR, though their practical impact on overpotential is shown to be less relevant. The capacity recovery after transferring cycled (“old”) LMR from Li cells to fresh Li cells rather points to other meaningful contributions to capacity fading than the inverse crosstalk.

Adsorptive Shield Derived Cathode Electrolyte Interphase Formation with Impregnation on LiNi0.8Mn0.1Co0.1O2 Cathode: A Mechanism-Guiding-Experiment Study.

Lithium difluoro(oxalate) borate (LiDFOB) contributes actively to cathode-electrolyte interface (CEI) formation, particularly safeguarding high-voltage cathode materials. However, LiNixCozMnyO2-based batteries benefit from the LiDFOB and its derived CEI only with appropriate electrolyte design while a comprehensive understanding of the underlying interfacial mechanisms remains limited, which makes the rational design challenging. By performing ab initio calculations, the CEI evolution on the LiNi0.8Co0.1Mn0.1O2 has been investigated. The findings demonstrate that LiDFOB readily adheres to the cathode via semidissociative configuration, which elevates the Li deintercalation voltage and remains stable in solvent. Electrochemical processes are responsible for the subsequent cleavage of B-F and B-O bonds, while the B-F bond cleavage leading to LiF formation is dominant in the presence of adequate Li+ with a substantial Li intercalation energy. Thus, impregnation is established as an effective method to regulate the conversion channel for efficient CEI formation, which not only safeguards the cathode's structure but also counters electrolyte decomposition. Consequently, in comparison to utilizing LiDFOB as an electrolyte additive, employing LiDFOB impregnation in the NCM811/Li cell yields significantly improved cycling stability for over 2000 h.

Multifunctional fluorinated phosphonate-based localized high concentration electrolytes for safer and high-performance lithium-based batteries

This study introduces a novel fluorinated phosphonate-based additive, Bis(2,2,2-trifluoroethyl)(methoxycarbonylmethyl)phosphonate (BTCMP), in a localized high-concentration electrolyte (LHCE) to address key challenges in lithium metal batteries (LMBs), such as dendritic lithium growth and porous electrode morphology. The pristine LHCE forms a fluorine-rich solid electrolyte interphase (SEI) layer, primarily composed of lithium fluoride (LiF). However, the pristine LHCE suffers from severe electrolyte decomposition, forming a thicker and more resistive cathode electrolyte interphase (CEI), leading to increased impedance and reduced cyclability. Interestingly, Density Functional Theory (DFT) investigations revealed that the BTCMP inclusion modifies the solvation structure by dispersing the aggregates into smaller fragments, facilitating easier Li+ migration than the pristine LHCE. The addition of BTCMP suppresses solvent decomposition as confirmed by an increasing trend in the lowest unoccupied molecular orbital (LUMO) of corresponding LHCE molecules. Further, the presence of BTCMP results in a thinner and more stable CEI, reducing electrolyte decomposition, maintaining better ion transport, and preserving the cathode's structural integrity, as supported by TEM and XPS analysis. The BTCMP-based F-rich LHCE retained 82 % of its initial capacity while maintaining a coulombic efficiency of 99.5 % after 200 cycles in a Li||LNMO cell while the pristine LHCE only retained 47.2 % of initial capacity post-150 cycles. Additionally, the flame-retardant properties of BTCMP-based LHCE highlight its safety compared to commercial electrolytes.

Fluorinated ester additive to regulate nucleation behavior and interfacial chemistry of room temperature sodium-sulfur batteries

Room temperature sodium-sulfur (RT Na-S) batteries are considered as advanced energy storage technology due to their low cost and high theoretical energy density. However, challenges such as the growth of sodium dendrite and dissolution of sodium polysulfides significantly hinder the electrochemical performance. Herein, we developed a propylene carbonate (PC)-based electrolyte with Methyl 2-Fluoroisobutyrate (MFB) as an additive. The ester group in the MFB additive is capable of participating in and reconfiguring the coordination of their Na+ solvated structures, thereby lowering the desolvation barrier and regulating the Na anode’s interfacial reaction and nucleation behavior. The polar C−F bond at the other end helps to reduce the lowest unoccupied molecular orbital (LUMO) energy of the MFB additive, enabling the preferential decomposition of MFB to form the F-rich inorganic phase strong polar solid electrolyte interphase (SEI), contributing to the inhibition of Na dendrite growth, the accumulation of dead Na. In addition, NaF-riched cathode electrolyte interphase (CEI) was also observed on sulfur-based cathode, which can effectively inhibited the shuttle effect. Consequently, the developed RT Na-S battery exhibit excellent electrochemical performance.

Air-stable manganese-based layered oxide cathode enabled by surface modification and doping strategy for advanced sodium-ion batteries

P2-type layered oxide materials have attracted widespread attention as advanced cathodes for sodium-ion batteries due to their excellent rate potential and attractive cost-effectiveness. However, the unexpected dissolution of transition metal (TM) ions and the annoying Jahn-Teller effect leading to rapid capacity fading and low capacity remain obstacles to their commercial applications. To tackle these handicaps, we introduced a synergistic effect based on surface modification and doping strategies to obtain air-stable sodium carbonate (Na2CO3) protective aluminum (Al)-doped manganese-based layered oxide cathode. The surface Na2CO3 nanolayer is created by converting residual alkali ions, which enhances the air stability of the cathode and scavenges hydrofluoric acid into the fluoride-rich cathode electrolyte interphase layer during cycling, resulting in a steady interfacial interaction. In addition, Al doping causes TMO6-octahedral shrinkage and inhibits structural distortion, thereby affecting structural evolution and phase transition. These findings provide valuable insights into improving the performance of layer oxide cathodes for next-generation low-cost batteries.

Cathode-Electrolyte Interphase Engineering toward Fast-Charging LiFePO4 Cathodes by Flash Carbon Coating.

Lithium iron phosphate (LiFePO4, LFP) batteries are widely used in electric vehicles and energy storage systems due to their excellent cycling stability, affordability and safety. However, the rate performance of LFP remains limited due to its low intrinsic electronic and ionic conductivities. In this work, an ex situ flash carbon coating method is developed to enhance the interfacial properties for fast charging. A continuous, amorphous carbon layer is achieved by rapidly decomposing the precursors and depositing carbon species in a confined space within 10 s. Simultaneously, different heteroatoms can be introduced into the surface carbon matrix, which regulates the irregular growth of cathode-electrolyte interphase (CEI) and selectively facilitates the inorganic region formation. The inorganic-rich, hybrid conductive CEI not only promotes electron and ion transport but also restricts parasitic side reactions. Consequently, LFP cathodes with fluorinated carbon coatings exhibited the highest capacity of 151 mAh g-1 at 0.2 C and 96mAhg-1 at 10 C, indicating their excellent rate capability over commercial LFP (58mAh g-1 at 10 C). This solvent-free, versatile surface modification is shown for other electrode materials, providing an efficient platform for electrode-electrolyte interphase engineering through a surface post-treatment.

Electrolyte with weakly coordinating solvents for high-performance FeS2 cathode

As the “blood” of batteries, the electrolyte is generally expected to be designed reasonably to meet the demands of stable energy storage in high energy density batteries. This study introduces a rational design for localized high-concentration electrolytes (LHCEs) by incorporating the weakly coordinating diluent 1, 1, 2, 2-tetrafluoro-1-methoxyethane (TFM) to modulate the solvation of Li+ alongside the anion and solvent 1, 2-diethoxyethane (DEE). The resulting LiFSI-DEE/2TFM electrolyte (1 M LiFSI in DEE/TFM at a ratio of 1:2, volume) demonstrates a significant efficacy in suppressing the dissolution of lithium polysulfides (LiPSs) while maintaining a good ionic conductivity. Moreover, this electrolyte facilitates the formation of a stable cathode-electrolyte interphase (CEI) and promotes uniform plating/stripping of Li+ at the lithium anode. Consequently, based on this electrolyte, the Li/FeS2 cells exhibit an exceptional specific capacity and a good cycling stability from room temperature to −20°C. Notably, even at −20°C, over 80 % of the room-temperature specific capacity (692.7 mAh g−1@150th) is retained for the cell using LiFSI-DEE/2TFM, showing its robust performance in challenging environments. Furthermore, the Li/FeS2 cell also demonstrates an outstanding durability at high current density (≥ 2 C) under room temperature.

Temperature‐Responsive Formation Cycling Enabling LiF‐Rich Cathode‐Electrolyte Interphase

AbstractFormation of LiF‐rich cathode‐electrolyte interphase is highly desirable for wide‐temperature battery, but its application is hindered by the unwanted side reactions associated with conventional method of introducing fluorinated additives. Here, we developed an additive‐free strategy to produce LiF‐rich cathode electrolyte interphase (CEI) by low‐temperature formation cycling. Using LiNi0.33Mn0.33Co0.33O2 as a model cathode, the atomic ratio of LiF in the CEI formed at −5 °C is about 17.7 %, enhanced by ~550 % compared to CEI formed at 25 °C (2.7 %). The underlying mechanism is uncovered by both experiments and theoretic simulation, indicating that the decomposition of LiPF6 to LiF is transformed into spontaneous and exothermic on positively charged cathode surface and lowering the temperature shift chemical equilibrium towards the formation of LiF‐rich CEI. Superior to conventional fluorinated additives, this approach is free from unwanted side reactions, imparting batteries with both high‐temperature (60 °C) cyclability and low‐temperature rate performance (capacity enhanced by 100 % at 3 C at −20 °C). This low‐temperature formation cycling to construct LiF‐rich CEI is extended to various cathode systems, such as LiNi0.8Mn0.1Co0.1O2, LiCoO2, LiMn2O4, demonstrating the versatility and potential impact of our strategy in advancing the performance and stability of wide‐temperature batteries and beyond.

A Synergistically Regulated Cathode/Electrolyte Interphase With High Stability and Rapid Zn2+ Migration Toward Advanced Flexible Zinc-Ion Batteries.

Na3V2(PO4)3(NVP), as a representative sodium superionic conductor with a stable polyanion framework, is considered a cathode candidate for aqueous zinc-ion batteries attributed to their high discharge platform and open 3D structure. Nevertheless, the structural stability of NVP and the cathode-electrolyte interphase (CEI) layer formed on NVP can be deteriorated by the aqueous electrolyte to a certain extent, which will result in slow Zn2+ migration. To solve these problems, doping Si elements to NVP and adding sodium acetate (NaAc) to the electrolyte are utilized as a synergistic regulation route to enable a highly stable CEI with rapid Zn2+ migration. In this regard, Ac- competitively takes part in the solvation structure of Zn2+ in aqueous electrolyte, weakening the interaction between water and Zn2+, and meanwhile a highly stable CEI is formed to avoid structural damage and enable rapid Zn2+ migration. The NVPS/C@rGO electrode exhibits a notable capacity of 115.5mAhg-1 at a current density of 50mAg-1 in the mixed electrolyte (3M ZnOTF2+3M NaAc). Eventually, a collapsible "sandwich" soft pack battery is designed and fabricated and can be used to power small fans and LEDs, which proves the practical application of aqueous zinc-ion batteries in flexible batteries.

External short circuit of lithium-ion battery after high temperature aging

The microscopic and macroscopic changes of lithium-ion batteries after high temperature cycling and their effect on external short circuit (ESC) are studied in this study. The results indicate that solid electrolyte interphase and cathode electrolyte interphase cover the surface of anode and cathode. Transition metal, Mn is dissolved from the cathode. Capacity and resistance decreases and increases after cycling at high temperature. The safety of batteries after ESC is ranked as: 70 % state of health (SOH) > 100 % SOH > 80 % SOH > 90 % SOH. Thermal runaway only occurs to battery with 90 % SOH after ESC. Increase of resistance after cycling affects heat generation during ESC less. Onset temperature and thermal runaway temperature increases and decreases owing to solid electrolyte interphase growth and Mn dissolution. Compared to fresh battery, safety of battery with 70 % SOH after ESC increases. Fast discharging causes side reactions for aged batteries, which also generate heat. The heat generation effect of fast discharging decreases with the decrease of SOH after 90 % SOH. Local micro internal short circuit causes more heat generation for aged batteries. The results are important for safety control of lithium-ion battery.

Sacrificial Additive C60-Assisted Catholyte Buffer Layer for Li1+xAlxTi2-x(PO4)3-Based All-Solid-State High-Voltage Batteries.

All-solid-state batteries with oxide electrolytes and high-nickel layered oxide cathodes (LiNixCoyMnzO2 and LiNixCoyAlzO2, x + y + z = 1, x ≥ 60%) have received widespread attention owing to their high energy density and high safety. However, they generally suffer from interfacial structural instability when coupled with solid-state electrolytes, which strongly diminishes the longevity of the battery. In this work, we propose adding a sacrificial additive C60 to the catholyte buffer layer between Li1.4Al0.4Ti1.6(PO4)3 (LATP) and LiNi0.8Co0.1Mn0.1O2 (NCM811) to enhance the electrochemical stability under high-voltage operating conditions. A uniform and robust cathode-electrolyte interphase (CEI) film enriched with LixPOyFz, LiPxFy, and C60Fn is spontaneously formed on the surface of the cathode particles. In addition, the NCM811/Li solid-state battery delivers a discharge capacity of 150.3 mAh g-1 with a retention of 85% after 200 charge-discharge cycles at 0.5 C. This study offers a practical approach toward realizing LATP-based all-solid-state high-voltage batteries characterized by exceptional cycling stability.

Regulating Li-ion solvation structure and Electrode-Electrolyte interphases via triple-functional electrolyte additive for Lithium-Metal batteries

LiPF6-based carbonate electrolytes have been widely utilized in commercial Li-ion batteries; however, they encounter significant interfacial stability challenges when implemented in high-energy–density lithium-metal batteries (LMBs). Herein, we introduce innovative N,N-diethylcyclohexanamine (NDA) as a triple-functional electrolyte additive to enhance the stability and compatibility of carbonate electrolytes. Due to the high electronegativity of amino group, NDA additive not only eliminates HF/H2O but also modifies the Li+ solvation structure, effectively reducing the electrolyte decomposition, suppressing the hydrolysis of LiPF6 and inhibiting the transition metal (TM) dissolution. Moreover, NDA facilitates the formation of Li3N-rich solid-/cathode-electrolyte interphase (SEI/CEI) layers thought preferential redox reactions at both the lithium metal anode (LMA) and Ni-rich cathode (LiNi0.8Co0.1Mn0.1O2, NCM811), which restrains the growth of Li dendrites, minimizes parasitic reactions, and promotes rapid Li+ transport. Therefore, the Li/NDA-added/Li symmetric cells exhibit remarkably stable cycling performance, lasting up to 630 h at 0.5 mA cm−2/0.5 mAh cm−2. Compared to the baseline cells, the Li/LiNi0.8Co0.1Mn0.1O2 cells with 0.5 wt% NDA show higher capacity retention after 300 cycles at 1C (85.9 % vs. 49.3 %) and superior rate performance, even at 9C. These unique features of NDA present a promising solution for addressing the interfacial deterioration issue of LMBs.

Revealing the Dynamic Evolution of Electrolyte Configuration on the Cathode-Electrolyte Interface by Visualizing (De)Solvation Processes.

Electrolyte engineering is crucial for improving cathode electrolyte interphase (CEI) to enhance the performance of lithium-ion batteries, especially at high charging cut-off voltages. However, typical electrolyte modification strategies always focus on the solvation structure in the bulk region, but consistently neglect the dynamic evolution of electrolyte solvation configuration at the cathode-electrolyte interface, which directly influences the CEI construction. Herein, we reveal an anti-synergy effect between Li+-solvation and interfacial electric field by visualizing the dynamic evolution of electrolyte solvation configuration at the cathode-electrolyte interface, which determines the concentration of interfacial solvated-Li+. The Li+ solvation in the charging process facilitates the construction of a concentrated (Li+-solvent/anion-rich) interface and anion-derived CEI, while the repulsive force derived from interfacial electric field induces the formation of a diluted (solvent-rich) interface and solvent-derived CEI. Modifying the electrochemical protocols and electrolyte formulation, we regulate the "inflection voltage" arising from the anti-synergy effect and prolong the lifetime of the concentrated interface, which further improves the functionality of CEI architecture.