Synergistic role of functional electrolyte additives containing phospholane-based derivative to address interphasial chemistry and phenomena in NMC811||Si-graphite cells

Sadeghi, Bahareh A.; Wölke, Christian; Pfeiffer, Felix; Baghernejad, Masoud; Winter, Martin; Cekic‐Laskovic, Isidora

doi:10.1016/j.jpowsour.2022.232570

Cited by 12 publications

(5 citation statements)

References 53 publications

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“…Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS) Sample Preparation: The SiO 2 -coated nanoparticles with a size of 55 nm used for SHINERS were synthesized and characterized according to the studies of Pfeiffer et al [61][62][63] After synthesis and purification, the nanoparticles were drop-casted on the glass windows of the air-tight optical cells (EL-CELL, ECC-Opto-Std). The windows were dried to remove moisture and transferred to an argon-filled glovebox for cell assembly.…”

Section: Methodsmentioning

confidence: 99%

Blended Salt Electrolyte Design for Enhanced NMC811||Graphite Cell Performance

Yan,

Shevchuk,

Wölke

et al. 2023

Small Structures

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The high energy density, nickel‐rich layered cathode material LiNi0.8Mn0.1Co0.1O2 (NMC811) is recognized as a promising candidate for next‐generation battery chemistries. However, due to their structural and interfacial instability, nickel‐rich NMC cathodes still face a number of challenges in practical application. For this reason, the design and development of novel electrolyte formulations, able to stabilize the nickel‐rich cathode|electrolyte interface, are highly demanded. In this work, a novel electrolyte is developed using lithium (difluoromethanesulfonyl) (trifluoromethanesulfonyl)imide (LiDFTFSI) and lithium hexafluorophosphate (LiPF6) as salt blend in an organic carbonate‐solvent based solvent mixture. The presence of LiDFTFSI notably enhances the electrochemical performance of the resulting NMC811||graphite cells. Further advancement of the considered cell chemistry is achieved by introducing the well‐known functional electrolyte additive vinylene carbonate (VC), which was found to feature a synergistic effect with LiDFTFSI. The formation of a homogenous, effective, and robust solid electrolyte interphase (SEI) as well as cathode electrolyte interphase (CEI) on the corresponding electrodes resulted in superior electrochemical performance.

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Section: Methodsmentioning

confidence: 99%

Blended Salt Electrolyte Design for Enhanced NMC811||Graphite Cell Performance

Yan,

Shevchuk,

Wölke

et al. 2023

Small Structures

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“…The surface protective layer formed on the positive electrode, typically denoted cathode electrolyte interphase (CEI), has been targeted in previous studies by including, for example, phosphate-or nitrile-based additives, [7][8][9][10][11] although the exact mechanisms of action are in most cases unknown. As such, concrete efforts of CEI-engineering are still on their infancy in comparison to their SEI counterpart.…”

Section: Introductionmentioning

confidence: 99%

A Hydridoaluminate Additive Producing a Protective Coating on Ni‐Rich Cathode Materials in Lithium‐Ion Batteries

Forero‐Saboya,

Moiseev,

Vlara

et al. 2024

Advanced Energy Materials

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To enhance the energy density of Li‐ion batteries, high‐capacity and high‐voltage cathode materials are needed. Recently, Ni‐rich layered oxides have attracted attention as they can offer ≈200 mAh g−1 when cycled up to 4.3 V. However, cycling these materials in their full capacity range often leads to excessive reactivity with the electrolyte, resulting in particle cracking, transition metal dissolution, and oxygen loss. In this study, the use of lithium hydridoaluminates as electrolyte additives is explored for lithium‐ion batteries based on nickel‐rich cathode materials. Being mild reducing agents, these additives act as HF scavengers, avoiding transition metal dissolution from the cathode. Additionally, their oxidation results in the formation of an Al‐rich protective layer on the cathode, which dampens the surface reactivity, preventing surface reconstruction and impedance build‐up. This study further stresses the important role of the cathode‐electrolyte interface phenomena on the capacity degradation of Ni‐rich cathode materials and provides a novel avenue for controlling this reactivity, thus extending their cycling life.

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“…However, we have shown in our previous work that additives can have a considerable impact on both positive and negative electrodes, directly or indirectly, even if they are designed for one of the two electrodes. [23][24][25] Herein we study the impacts of DTDPh in LNO||graphite cell chemistry by means of electrochemical and spectroscopic techniques and demonstrate a large improvement of cycling performance that is higher than what can be achieved with VC. In addition, we found strong evidence for an interaction between DTDPh and VC that diminishes the performance of the resulting cells and discuss a possible mechanism for this interaction based on density functional theory (DFT) calculations.…”

Section: Introductionmentioning

confidence: 99%

Single vs. Blended Electrolyte Additives: Impact of a Sulfur-Based Electrolyte Additive on Electrode Cross-talk and Electrochemical Performance of LiNiO2||Graphite Cells

Wölke,

Benayad,

Lai

et al. 2024

Preprint

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Lithium nickel oxide (LNO) is an attractive positive electrode active material for lithium ion batteries (LIBs) due to its high reversible specific capacity and absence of cobalt. Nevertheless, it is prone to structural instabilities that lead to rapid capacity fading, safety concerns and shows in average a lower voltage than mixtures with cobalt, limiting its applicability to date. Herein we introduce the sulfur-based electrolyte additive, benzo[d][1,3,2]dioxathiole 2,2-dioxide (DTDPh), to stabilize the LNO electrode and study its effects on interphase compositions by means of complementary electrochemical and spectroscopic techniques. Obtained results demonstrate an improved galvanostatic cycling performance in terms of cycle life and achievable specific discharge capacity that significantly outperform the common film-forming additive vinylene carbonate (VC). The cycle life was increased from 102 to 147 cycles compared to the baseline electrolyte and the accumulated discharge energy until end of life was increased by 45%. This study furthermore provides strong evidence of a significant cross-talk and negative interplay between DTDPh and VC when both are present in the electrolyte formulation. Mechanistic consideration based on density functional theory (DFT) calculations suggest the formation of mobile poly(VC) species, which is supported by the results of post mortem analysis of the resulting interphases.

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Synergistic role of functional electrolyte additives containing phospholane-based derivative to address interphasial chemistry and phenomena in NMC811||Si-graphite cells

Cited by 12 publications

References 53 publications

Blended Salt Electrolyte Design for Enhanced NMC811||Graphite Cell Performance

Blended Salt Electrolyte Design for Enhanced NMC811||Graphite Cell Performance

A Hydridoaluminate Additive Producing a Protective Coating on Ni‐Rich Cathode Materials in Lithium‐Ion Batteries

Single vs. Blended Electrolyte Additives: Impact of a Sulfur-Based Electrolyte Additive on Electrode Cross-talk and Electrochemical Performance of LiNiO2||Graphite Cells

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