Electrode-electrolyte Interphase Research Articles

Bi-Based Electrode Materials for Alkali Metal-Ion Batteries.

Alkali metal (Li, Na, K) ion batteries with high energy density are urgently required for large-scale energy storage applications while the lack of advanced anode materials restricts their development. Recently, Bi-based materials have been recognized as promising electrode candidates for alkali metal-ion batteries due to their high volumetric capacity and suitable operating potential. Herein, the latest progress of Bi-based electrode materials for alkali metal-ion batteries is summarized, mainly focusing on synthesis strategies, structural features, storage mechanisms, and the corresponding electrochemical performance. Particularly, the optimization of electrode-electrolyte interphase is also discussed. In addition, the remaining challenges and further perspectives of Bi-based electrode materials are outlined. This review aims to provide comprehensive knowledge of Bi-based materials and offer a guideline toward more applications in high-performance batteries.

Controlling Ion Coordination Structure and Diffusion Kinetics for Optimized Electrode-Electrolyte Interphases and High-Performance Si Anodes

The cycling performance of batteries is largely determined by the electrode-electrolyte interphase associated with the chemical and electrochemical properties of electrolyte salts and solvents. In ...

Ion-Transport-Rectifying Layer Enables Li-Metal Batteries with High Energy Density

<h2>Summary</h2> The lithium-metal battery (LMB) holds great promise for various applications for which high energy density is required; the adoption of LMB, however, is limited by poor performance of the lithium-metal anode (LMA), which is intrinsically associated with the unregulated ion transport and reaction. By coating an ion-transport rectifier on the LMA, which was synthesized from a metal-organic framework with high lithium-ion transference number and conductivity, we report here the fabrication of an LMB with a thin Li anode (≤50 μm), a thick LiCoO₂ cathode (4 mAh cm⁻²), and lean electrolyte condition. Such an LMB can potentially deliver high gravimetric and volumetric energy density exceeding that of state-of-the-art lithium-ion batteries. This work offers a new strategy to regulate the ion transport and reaction at electrode-electrolyte interphase, facilitating the development of practical LMB for a broad range of applications.

Reversible Deposition and Stripping of the Cathode Electrolyte Interphase on Li2RuO3.

Performance decline in Li-excess cathodes is generally attributed to structural degradation at the electrode-electrolyte interphase, including transition metal migration into the lithium layer and oxygen evolution into the electrolyte. Reactions between these new surface structures and/or reactive oxygen species in the electrolyte can lead to the formation of a cathode electrolyte interphase (CEI) on the surface of the electrode, though the link between CEI composition and the performance of Li-excess materials is not well understood. To bridge this gap in understanding, we use solid-state nuclear magnetic resonance (SSNMR) spectroscopy, dynamic nuclear polarization (DNP) NMR, and electrochemical impedance spectroscopy (EIS) to assess the chemical composition and impedance of the CEI on Li2RuO3 as a function of state of charge and cycle number. We show that the CEI that forms on Li2RuO3 when cycled in carbonate-containing electrolytes is similar to the solid electrolyte interphase (SEI) that has been observed on anode materials, containing components such as PEO, Li acetate, carbonates, and LiF. The CEI composition deposited on the cathode surface on charge is chemically distinct from that observed upon discharge, supporting the notion of crosstalk between the SEI and the CEI, with Li+-coordinating species leaving the CEI during delithiation. Migration of the outer CEI combined with the accumulation of poor ionic conducting components on the static inner CEI may contribute to the loss of performance over time in Li-excess cathode materials.

Spray-assembled nanoscale cobalt-oxide as highly efficient and durable bifunctional electrocatalyst for overall water splitting

Water splitting is an overgrowing research field and there is a huge challenge to develop easily accessible and applied methods for facile fabrication of durable electroactive thin-film catalysts. Here we demonstrate a simple cost-effective spray-coating strategy to develop ultrathin and highly crystalline CoOx nanoparticulate thin-films as a bifunctional electrocatalyst for overall water splitting. During electrocatalysis, nanoscale surface-coated CoOx (SC-CoOx NPs) exhibits high activity while initiating OER and HER just at 1.48 VRHE and 0.22 VRHE, respectively, and displayed current decades for OER and HER at an overpotential of 300 mV and 350 mV, respectively. Furthermore, the high electrochemically active surface area of 301 cm2, facile electrode kinetics and low charge transfer resistance at electrode-electrolyte interphase are observed that promote efficient electron transfer and facilitate adsorption/desorption of various intermediates during water splitting process thus making it energy efficient. DFT calclations also suggest that the electrode is very feasible for water oxidation catalysis which is ruling reaction under employed conditions. The electrocatalyst also presented superior long-term durabilities during extended period water electrolysis experiments. The present material, method and approach of growing metal-oxide nanoscale and thin-film assemblage of catalytic materials can offer an exciting and straightforward approach for producing highly applied catalytic materials.

Designing Polymers for Electrochemical Energy Conversion & Storage

Rational design of the electrode-electrolyte interphase is essential to stabilize the electrodeposition of reactive metals like lithium, irrespective of the nature of electrolyte (liquid or solid-state). Thus, it is important to design an artificial interfacial layer that can accommodate the stress generated due to the volume changes during battery operation and at the same time maintain ionic continuity. In our work, we design novel materials based on dynamic ionic bond polymer networks that can be used as a coating on metal anode for enhancing the electrochemical stability. It was seen that polymers comprising of dynamic bonding groups are more effective in preventing the morphological instabilities compared to covalently bonded rigid polymers and crosslinked elastomers. The stabilization mechanism of the dynamic polymeric coatings is understood to arise from the spontaneous structural response of the polymer in response to the roughening electrode during electrodeposition. As the polymer coating is free to flow, if there is a ‘hotspot’ (uneven deposit) on the surface of the lithium metal, the dynamic polymer coating can rearrange and cover these regions resulting in increased overpotential, such that the successively Li+ ions deposit on the flatter regions resulting in a uniformity of deposition. In my talk, I will discuss the mechanics, microstructure, and 'self-healing properties' of these dynamic polymer networks and the relationship with their electrochemical functions.

Direct dissolution of uranium oxides in deep eutectic solvent: An insight using electrochemical and luminescence study

Nuclear energy is going to be the most potential option for solving the global energy crisis owing to its cost efficiency and environment friendliness. This work was carried with objective to propose a cheap, non-toxic and green solvent for dissolution of actinide oxide which is highly relevant from nuclear fuel reprocessing point of view. This prompted us to take the challenging research problem of investigating the dissolution behavior of different Uranium oxides (UO3, UO2 and U3O8) in p-Toluenesulfonic acid monohydrate (PTSA) based deep eutectic solvent (DES) and investigating its redox behavior and speciation using cyclic voltammetry (CV) and photoluminescence spectroscopy. We initiated with synthesis of relatively new class of DES consisting of Choline chloride (ChCl) and PTSA using mechanochemical route. The metal concentration dissolved was determined by EDXRF and it was found that PTSA: ChCl (1:2) was better in terms of solubility for uranium oxides as compared to PTSA: ChCl (1:1) and Malonic acid: ChCl (1:1). The formation of DES consisting of Hydrogen bonding network is confirmed using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. It could also be found that uranium oxide dissolution doesn’t distort the H-bonding network of DESs. Based on CV results it was proposed that U(VI)/U(V) reduction is controlled not only by diffusion of U(VI) ion in PTSA:ChCl (1:2), but also by the kinetics of the charge transfer reaction occurring at the electrode-electrolyte interphase. Luminescence spectroscopy suggested U(VI) in DES has U–O single bond moiety, having UO66− local coordination with excited state lifetime of 9.5 μs.

Renovating the electrode-electrolyte interphase for layered lithium- & manganese-rich oxides

Layered lithium- & manganese-rich oxides (LMR), with their high capacity and cost-effective advantage, are considered as a potent alternative of the next-generation cathode material for lithium-ion batteries. The behaviors of the electrode-electrolyte interphase (EEI) are crucial to the electrochemical properties of LMR as a cathode material operating at wide voltage regions (from 2 to 4.8 ​V). Nonetheless, the understanding of EEI for LMR materials and the related renovation techniques are somewhat lacking. Herein, we gain insight into the EEI change mechanism for LMR materials during long electrochemical cycles and demonstrate a renovating method to mitigate its deterioration. As for the pristine electrode based on LMR materials, the increasing amount of POxFyz− and metal fluorides lead to unpleasant degradation for both the EEI and the active material particle, causing evident performance decay. Whereas, the lithium phosphate, if employed in the electrode, effectively enhances the lithium ions transfer, impedes the decomposition of electrolyte salt, and leads to a more stable EEI, thus promoting the electrochemical performances of LMR materials. All results indicate that the EEI should be one of the critical components for comprehensively understanding the LMR material, and the success renovation by the lithium phosphate offers a new orientation for those intrinsic drawbacks of LMR material.

Modeling Electrocatalytic Oxidation of Formic Acid at Platinum

The formic acid oxidation reaction (FAOR) is a model electrocatalytic reaction involving multiple proton-coupled electron transfer steps. Despite of repeated research extending over more than fifty years, the FAOR is still an active research field in which several important questions including reaction mechanisms, the activity dependence on the electrode structure, the hysteresis between positive- and negative-going scan in cyclic voltammetry (CV), and, especially, the pH effect, remain elusive yet. To shed some light on these puzzles, we herein develop a microkinetic model for the FAOR at Pt(111) which uses a reaction mechanism supported by microscopic and mechanistic information from density functional theory calculations and spectroscopic characterizations, formulates the mechanism using fully microkinetic modeling without designating a rate-determining step, and incorporates double-layer effects by means of a mean-field description for the electrode-electrolyte interphase. Moreover, chemisorbed intermediates play multifaceted roles in this formulism: they are reactants with lateral interactions, site-blockers, as well as modifiers of the double-layer structure and properties. The model is parameterized using CV data of Pt(111) in perchlorate electrolyte with different pHs, revealing that HCOOm is the main active intermediate with HCOO− as the main precursor. COad on defect sites induces the voltage hysteresis through modifying surface charging relation (the main effect) and blocking adsorption sites (the minor effect). It is also found that the higher current density as the pH increases from 0.11 to 1.42 is the result of two opposing factors: higher concentration of HCOO− in bulk solution and stronger double layer effects that suppress HCOOm formation. The presented work demonstrates that consideration of double-layer effects and an integrated view of multifaceted roles of reaction intermediates are a sheer necessity for FAOR.

Additive-Mediated Electrode-Electrolyte Interphase for Long Service-Life, High-Nickel Cathodes for Lithium-Ion Batteries

With a dramatically increasing demand for electric vehicles (EVs), a driving range of minimum 300 miles is a must to satisfy the market requirement. Such a demand has motivated enormous efforts focused on the development of high-Ni layered oxide cathodes (LiNi1 −xMxO2 with M = Mn and Co and (1 − x) > 0.9). However, degradation of the electrode–electrolyte interphase, which is a major cause for poor cycle life, remains as a critical problem that hinders their widespread application, especially when the voltage exceeds the HOMO (highest occupied molecular orbital, ≈ 4.3 V vs. Li/Li+) of the organic carbonate electrolytes used. Specifically, the parasitic electrolyte decomposition occurs on the charged cathode surface, resulting in the formation of cathode–electrolyte interphase (CEI) with complicated surface chemistry. Moreover, the surface degradation on cathode usually involves active mass dissolution, which is a common phenomenon in various cathodes. Subsequently, the dissolved transition-metal ions reach the anode side through chemical crossover and poison the anode–electrolyte interphase (AEI) on the graphite surface. Thus, understanding the chemical and electrochemical reactions between the electrode and electrolyte, which influences the composition, microstructure, and chemical properties of the formed electrolyte–electrolyte interphases (EEIs), is crucial to establishing high-energy-density Li-ion batteries with long, stable service life. Herein, with an ultrahigh-Ni layered oxide (LiNi0.94Co0.06O2) as a model cathode and lithium bis(oxalate) borate (LiBOB) as a model electrolyte additive, the EEI chemical and physical property changes on both the cathode and anode are elucidated. Moreover, the layered architecture of the CEI and AEI at the nanometer scale is revealed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and the correlation between CEI and AEI properties is illustrated. On a chemical perspective, the tuned EEIs are configured with B x O y species and less ethylene carbonate/LiPF6 decomposition products, which endows the CEI with extreme robustness against electrochemical abuse and better Li-ion diffusivity within both the CEI and AEI. Moreover, it reveals that the modification of the surface chemistry on the cathode side would beneficially change the physical stacking behavior of components on the AEI. AEI is reconstructed from a thick “three-layer” architecture (F-enriched exterior layer, O-dominating intermediate layer, and Li-containing interior layer) to a thin “two-layer” architecture (O-enriched exterior layer and Li-dominating interior layer), benefiting from the B x O y enrichment within the EEI. As a result, superior electrochemical performance is achieved by manipulating the electrode surface chemistry even under a moderately high operating voltage (4.4 V vs Li/Li+), and the capacity retention is greatly increased from 61 to 80% after 500 cycles in a full cell assembled with graphite anode. Figure 1

On the use of guanidine hydrochloride soft template in the synthesis of Na2/3Ni1/3Mn2/3O2 cathodes for sodium-ion batteries

Several P2-Na2/3Ni1/3Mn2/3O2 layered oxides have been prepared by a modified synthesis procedure using guanidine hydrochloride as a soft template. X-ray diffraction patterns will reveal a decrease of both crystallite size and strain for guanidine hydrochloride treated samples, favoring sodium accessibility at the electrode/electrolyte interface. Also, guanidine hydrochloride promotes anisotropic particles for intermediate amounts. This specific morphology may contribute to a partial suppression of the P2-O2 phase transition. Galvanostatic tests at different rates and potential windows will evidence better capacity retention and low charge-discharge hysteresis for NaNMO-2% in close relationship with the low internal resistance values at the electrode-electrolyte interphase and apparent diffusion coefficients determined by impedance spectroscopy. A performing full sodium-ion cell will demonstrate the reliability of this material as an electrode for Na-ion cells.

Graphene as Vehicle for Ultrafast Lithium Ion Capacitor Development Based on Recycled Olive Pit Derived Carbons

Herein we report a series of lithium ion capacitors (LICs) with extraordinary energy-to-power ratios based on olive pit recycled carbons and supported on graphene as a conducting matrix. LICs typically present limited energy densities at high power densities due to the sluggish kinetics of the battery-type electrode. To circumvent this limitation, the hard carbon (HC) was embedded in a reduced graphene oxide (rGO) matrix. The addition of rGO into the negative electrode not only forms a 3D interpenetrating carbon network but also wraps HC particles, facilitating ion diffusion and enhancing the electronic conductivity notably at high power densities. Electrochemical impedance spectroscopy (EIS) analysis reveals that charge-transfer resistance at electrode-electrolyte interphase and the charge-transport resistance within the electrode are considerably lower in the presence of rGO. In addition, charge-transport resistance remains constant upon cycling even at increasing current densities. Capacity gain at high current densities, owing to the reduction of the electrode resistance, triggers the overall LIC performance, allowing for the assembly of an ultrafast LIC delivering up to 200 Wh kg−1AM at low power rates and 100 Wh kg−1AM at a power of 10 kW kg−1AM.

Redox processes in sodium vanadium phosphate cathodes - insights from operando magnetometry.

Operando magnetic susceptibility measurements of sodium ion cathode materials during repetitive electrochemical cycling enable a continuous and bulk sensitive monitoring of the transition metal oxidation states. Such measurements on NaxV2(PO4)3 identified vanadium to be the only ion undergoing oxidation/reduction processes upon battery operation. For the initial battery charging-discharging cycle as well as for the first cycle after prolonged room temperature storage, however, peculiarities within the magnetic susceptibility measurements indicate parasitic side reactions, likely on the cathode surface.

Extending the Service Life of High‐Ni Layered Oxides by Tuning the Electrode–Electrolyte Interphase

AbstractAs a high‐energy‐density cathode for Li‐ion batteries, high‐Ni layered oxides, especially with ultrahigh Ni‐content, suffer from short lifespans, due in part to their unstable electrode–electrolyte interphase (EEI). Herein, the cycle life of LiNi0.94Co0.06O2 is greatly extended by manipulating the EEI with a lithium bis(oxalate) (LiBOB) additive even when operated at a moderately high voltage (4.4 V vs Li/Li+). Impressively, the capacity retention can be increased from 61 to 80% after 500 cycles in a full cell paired with a graphite anode. Additionally, the presence of LiBOB enables a robust boron‐ and oxygen‐enriched EEI that effectively inhibits continual electrolyte decomposition and offers a stable cathode surface. Moreover, the layered architecture of the cathode–electrolyte interphase (CEI) and the anode–electrolyte interphase (AEI) at the nanometer scale is revealed by time‐of‐flight secondary ion mass spectrometry. It is demonstrated that the cathode surface chemistry can significantly influence the AEI both chemically and physically, and AEI is modified from a thick “three‐layer” to a thin “two‐layer” architecture by tuning the cathode surface chemistry with LiBOB. This work presents a correlation between the EEI characteristics and battery performance and highlights the significance of manipulating surface chemistry in developing stable high‐energy‐density Li‐ion batteries.

Study of the Influence of Carbon Additive Content in LiMn0.5Ni1.5O2 Cathodes in Lithium Ion Batteries

LiMn0.5Ni1.5O2 is one of the most important materials for high voltage Lithium Ion batteries. Due to the high operation voltage, the LiMn0.5Ni1.5O2 – electrolyte interphase suffers high reactivity which limits the cyclability of the electrodes. Several modifications to the electrolyte, cathode material, and inclusion of additives in both phases have been investigated, however although they have provided slight improvements, the reasons behind the stability enhancement still are not fully understood [1]. Additionally, the presence of carbon additives has also been reported to influence the initial capacity and cyclability of the cathodes; however, the great variety of cathode composite compositions, type of carbon additives and experimental conditions makes difficult a fair comparison between them. In this work the influence of carbon additives at two compositions (2 and 10%) is studied by cyclic voltammetry charge and discharge curves and Electrochemical Impedance spectroscopy (EIS), the cyclability in both cases resulted very high with high coulombic efficiency close to 100% with Li anodes. The EIS spectra were adjusted to several equivalent electric circuits, while most of them results in a fair agreement, the explications derived from them are not applicable to all cases, moreover, a phenomenological interpretation was proposing which resulted in excellent xi2 adjustment (10-5) which overpasses by far state of the art results (10-3) with limited phenomenological information. In this work the EIS was applied at several conditions of the electrode and in general it was observed an enormous increase of charge transfer resistance as cycling goes on. However, the lower carbon content results in an even faster degradation process which is also accelerated by longer times at higher voltages. Therefore, the carbon additive also has a big influence on the reactivity of the electrode-electrolyte interphase and can serve as additional tool to increase the cyclability of the electrodes. Acknowledgements This work was supported, GR thanks (project seciti/080/2017) IG thanks CONACYT (proyect 237343) for financial support. G. Guzman is grateful to CONACYT for the scholarship granted to pursue his doctoral studies. [1] Kang-Joon Park,a Byung-Beom Lim,a Moon-Ho Choi,a Hun-Gi Jung, Yang-Kook Sun, Marta Haro, Nuria Vicente, Juan Bisquert and Germá Garcia-Belmonte, J. Mater. Chem. A, 2015, 3, 22183

Insights into the Improved High-Voltage Performance of Li-Incorporated Layered Oxide Cathodes for Sodium-Ion Batteries

Summary By virtue of their prominent advantages in terms of capacity and voltage output and cost, O3-type layered transition-metal oxides are considered promising cathode materials for sodium-ion batteries (SIBs). However, their unstable electrochemistry at high voltages due to complex multiphase evolution in the bulk structure and continuous degradation of the electrolyte-cathode interphase hampers their practical viability. Here, we reveal a dual-stabilization effect of the cation dopants on the evolution of the bulk structure and electrode-electrolyte interphase of a Li-substituted O3-type cathode upon Na (de)intercalation. The incorporation of Li into the transition-metal layer could mitigate the Jahn-Teller distortion of the Ni3+ ion and prevent the loss of active transition-metal ions so that the unfavorable high-voltage phase transition and the degradation of the electrolyte-cathode interphase are suppressed. As a result, the Li-incorporated cathode material displays a high reversible capacity with good high-voltage durability to facilitate its service in high-energy-density SIBs.

Interphases in Sodium‐Ion Batteries

AbstractSodium‐ion batteries (SIBs) as economical, high energy alternatives to lithium‐ion batteries (LIBs) have received significant attention for large‐scale energy storage in the last few years. While the efforts of developing SIBs have benefited from the knowledge learned in LIBs, thanks to the apparent proximity between Na‐ions and Li‐ions, the unique physical and chemical properties of Na‐ions also distinctly differ themselves from Li‐ions. It is expected that SIBs have drastically different electrode material structure, solvation–desolvation behavior, electrode–electrolyte interphase stabilities, ion transfer properties, and hence electrochemical performance of batteries. In this review, the authors comprehensively summarize the current understanding of the anode solid electrolyte interphase and cathode electrolyte interphase in SIBs, with an emphasis on how the tuning of the stability and ion transfer properties of interphases fundamentally determines the reversibility and efficiency of electrochemical reactions. Through these carefully screened references, the authors intend to reveal the intrinsic correlation between the properties/functionalities of the interphases and the electrochemical performance of batteries.

(Invited) Capacitive Deionization of High-Salinity Water Using Ion-Exchange Membranes

It is known that capacitive deionization (CDI) is not suitable for direct desalination of seawater because of its high salinity (~ 35 g L−1) and the limit in applied potential to avoid water electrolysis and oxidation of chloride ions. It has recently been reported, however, that the potential window can be expanded with the formation of an electrode-electrolyte interphase when using highly concentrated aqueous electrolyte. Studies also have proven that increasing ion concentration can greatly enhance the ion capacity of the electrodes. In addition, ion-exchange membranes (IEMs) can be used to control the electrode performance and allow application of reverse potential for electrodesorption. Here, we present the possibility to directly desalt high-salinity water and seawater through membrane CDI (MCDI). An MCDI cell was symmetrically assembled with anion and cation exchange membranes attached respectively to the anode and cathode. Our results show that the MCDI cell equipped with mesoporous carbon can remove 66.7 mg sodium chloride per gram of carbon, while the CDI cell alone (without membranes) could only remove 8.5 mg g−1 under the same conditions. Similarly, the MCDI cell equipped with carbon aerogel demonstrated a salt removal capacity of 37.3 mg g−1 in comparison with 12.9 mg g−1 of the CDI cell. These results indicate that the MCDI cell, assisted with IEMs and overpotential, can directly desalt high-salinity water regardless of the electrode material. Moreover, IEMs can prevent coion desorption at the beginning of the adsorption stage, as well as counterion adsorption at the beginning of the desorption stage, which can increase energy efficiency. For high-salinity water desalination, electrode regeneration is challenging. By applying a reversed low potential and controlling the desorption time, electrode regeneration can become effective. The presentation will include a review of CDI approaches, motivation for overpotential CDI supported by neutron imaging of electrodes and basic electrochemical experiments, characterization of electrode materials, a discussion of overpotential CDI and MCDI results including energy requirements, and a discussion of remaining challenges for direct desalting of high-salinity water via MCDI.

Influence of Using Metallic Na on the Interfacial and Transport Properties of Na-Ion Batteries

Na2Ti3O7 is a promising negative electrode for rechargeable Na-ion batteries; however, its good properties in terms of insertion voltage and specific capacity are hampered by the poor capacity retention reported in the past. The interfacial and ionic/electronic properties are key factors to understanding the electrochemical performance of Na2Ti3O7. Therefore, its study is of utmost importance. In addition, although rather unexplored, the use of metallic Na in half-cell studies is another important issue due to the fact that side-reactions will be induced when metallic Na is in contact with the electrolyte. Hence, in this work the interfacial and transport properties of full Na-ion cells have been investigated and compared with half-cells upon electrochemical cycling by means of X-ray photoelectron spectroscopy (conventional XPS and Auger parameter analysis) and electrochemical impedance spectroscopy. The half-cell has been assembled with C-coated Na2Ti3O7 against metallic Na whilst the full-cell uses C-coated Na2Ti3O7 as negative electrode and NaFePO4 as positive electrode, delivering 112 Wh/kganode+cathode in the 2nd cycle. When comparing both types of cells, it has been found that the interfacial properties, the OCV (open circuit voltage) and the electrode–-electrolyte interphase behavior are more stable in the full-cell than in the half-cell. The electronic transition from insulator to conductor previously observed in a half-cell for Na2Ti3O7 has also been detected in the full-cell impedance analysis.

On the Electrochemical Properties and Interphase Composition of Graphite: PVdF-HFP Electrodes in Dependence of Binder Content

Poly(vinylidene-difluoride) (PVdF) based polymers constitute the most commonly used binders for lithium-ion battery electrodes. In scientific studies, the binder content often exceeds commercially meaningful amounts. At the same time, the battery electrode performance can in various ways be coupled to its binder content, partly due to its influence on the surface properties. For example, an optimum binder content of around 5 wt% has been reported. In this study, graphite:PVdF-HFP electrodes containing 2.5, 5 and 10 wt% of PVdF-HFP are investigated, and their electrochemical behavior are put into context of the electrode-electrolyte interphase of the different formulations. Although the electrodes display similar electrochemical behavior, the SEI layer composition and thickness, analyzed by photoelectron spectroscopy, vary notably depending on binder content. It was found that a binder content of 5 wt% maintained the best cycling stability and also exhibited a thinner SEI layer with a larger fraction of inorganic components. In contrast to higher binder contents, where the binder covers most of the surface, larger parts of the active material are exposed directly to the electrolyte with binder contents of 2.5–5 wt%. The formation of a thinner, yet protective, SEI layer is beneficial for cycling performance of the graphite electrode.