Kerr gated Raman spectroscopy of LiPF<sub>6</sub>salt and LiPF<sub>6</sub>-based organic carbonate electrolyte for Li-ion batteries

Cabo‐Fernández, Laura; Neale, Alex R.; Braga, Filipe; Sazanovich, Igor V.; Kostecki, Robert; Hardwick, Laurence J.

doi:10.1039/c9cp02430a

Cited by 40 publications

(43 citation statements)

References 39 publications

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“…These peaks are significantly suppressed when the potential drops to 1.6 V (vs Li/Li + ) and almost disappear as the potential further decreases to 0.82 V (vs Li/Li + ), indicating the transformation of α-Fe 2 O 3 to Li x Fe 2 O 3 or Li 2 Fe 2 O 3 . When the potential further drops to 0.72 V (vs Li/Li + ), a different set of characteristic peaks located at 518, 718, 742, 894, 906, 916, and 972 cm –1 emerges, which are attributable to DMC (518, 916, and 972 cm –1 ), EC (718, 894, and 906 cm –1 ), and PF 6 – (742 cm –1 ) of the electrolyte. − Furthermore, the conversion reaction occurring at around 0.8 V (vs Li/Li + ) leads to the formation of Fe 0 nanoparticles. The presence of Fe 0 nanoparticles enhances the Raman signals of the materials adsorbed on the surfaces of Fe 0 nanoparticles, which explains why the characteristic peaks of the electrolyte components emerge as the potential decreases to 0.72 V (vs Li/Li + ).…”

Section: Resultsmentioning

confidence: 99%

Hollow Porous α-Fe₂O₃ Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Tan

et al. 2021

ACS Sustainable Chem. Eng.

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The lithium-ion capacitor (LIC) is a novel energy storage device, pairing battery-type anodes with capacitor-type cathodes, capable of delivering high energy and power densities. The anode materials of excellent high-rate capability, however, are required to resolve the common kinetics imbalance issue for high-performance LICs. A simple one-step solvothermal, metal–organic framework (MOF) evolved process was developed to synthesize hollow porous α-Fe2O3 nanoparticles (α-Fe2O3 HPNPs) as an anode material of excellent high-rate capability for high-performance LICs. The α-Fe2O3 HPNP anode achieved an excellent high-rate capability and cycling stability, through accelerating lithium-ion diffusions with the porous shell and shortening lithium-ion diffusion paths and buffering large volume variations during cycling with the confined hollow space. The quantitative kinetic analyses showed that capacitive processes are the main contributor to the capacity generation of the α-Fe2O3 HPNP anode, making the α-Fe2O3 HPNP an excellent match with capacitor-type cathodes, glucose-derived carbon nanospheres (GCNS) of high specific surface areas, for the assembly of LICs. The α-Fe2O3 HPNP//GCNS LIC delivered a high energy density of 107 Wh kg–1 at 0.24 W kg–1 and maintained an adequate energy density of 86 Wh kg–1 at an extremely high power density of 9.68 kW kg–1. Moreover, it exhibited a high capacity retention of 84% after 2500 cycle operations at 1 A g–1. Both materials and nanostructure of electrodes play a key role for high-performance LICs, and the hollow porous nanoparticulate structure is proven to be an advantageous nanostructure for the anode materials of LICs.

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Section: Resultsmentioning

confidence: 99%

Hollow Porous α-Fe₂O₃ Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Tan

et al. 2021

ACS Sustainable Chem. Eng.

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“…Although LiPF 6 has been shown to induce a fluorescence background in Raman spectroscopy experiments, its strong PF Raman-active band would make it an ideal candidate for further studies. 45 There is little doubt, therefore, that many current and future electrolyte mixtures benefit from measuring electrolyte properties in this manner. To increase the viability of the presented method further, more advanced Raman techniques such as stimulated Raman spectroscopy (SRS) could be employed.…”

Section: Discussionmentioning

confidence: 99%

Characterising lithium-ion electrolytes via operando Raman microspectroscopy

et al. 2021

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Knowledge of electrolyte transport and thermodynamic properties in Li-ion and beyond Li-ion technologies is vital for their continued development and success. Here, we present a method for fully characterising electrolyte systems. By measuring the electrolyte concentration gradient over time via operando Raman microspectroscopy, in tandem with potentiostatic electrochemical impedance spectroscopy, the Fickian “apparent” diffusion coefficient, transference number, thermodynamic factor, ionic conductivity and resistance of charge-transfer were quantified within a single experimental setup. Using lithium bis(fluorosulfonyl)imide (LiFSI) in tetraglyme (G4) as a model system, our study provides a visualisation of the electrolyte concentration gradient; a method for determining key electrolyte properties, and a necessary technique for correlating bulk intermolecular electrolyte structure with the described transport and thermodynamic properties.

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“…The ideal sensor would (i) not perturb the device operation, (ii) be nondestructive, (iii) not compromise safety, (iv) work during battery operation, and (v) be easily combined with other cell components without affecting the operation and lifetime of the battery 23 . Suitable sensing probes include the molecular vibrational spectroscopies, FT-IR and Raman 24 – 26 , which have recently gained popularity in battery science due to their ability to provide a safe, fast, and label-free analysis of the chemical composition and evolution of different battery components. Recent examples are the in situ FT-IR analysis of the oxidation of EC at the LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) interface 10 , and in situ Raman studies on graphite electrodes 27 , 28 .…”

Section: Introductionmentioning

confidence: 99%

Hollow-core optical fibre sensors for operando Raman spectroscopy investigation of Li-ion battery liquid electrolytes

et al. 2022

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Improved analytical tools are urgently required to identify degradation and failure mechanisms in Li-ion batteries. However, understanding and ultimately avoiding these detrimental mechanisms requires continuous tracking of complex electrochemical processes in different battery components. Here, we report an operando spectroscopy method that enables monitoring the chemistry of a carbonate-based liquid electrolyte during electrochemical cycling in Li-ion batteries with a graphite anode and a LiNi0.8Mn0.1Co0.1O2 cathode. By embedding a hollow-core optical fibre probe inside a lab-scale pouch cell, we demonstrate the effective evolution of the liquid electrolyte species by background-free Raman spectroscopy. The analysis of the spectroscopy measurements reveals changes in the ratio of carbonate solvents and electrolyte additives as a function of the cell voltage and show the potential to track the lithium-ion solvation dynamics. The proposed operando methodology contributes to understanding better the current Li-ion battery limitations and paves the way for studies of the degradation mechanisms in different electrochemical energy storage systems.

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Kerr gated Raman spectroscopy of LiPF₆salt and LiPF₆-based organic carbonate electrolyte for Li-ion batteries

Abstract: Kerr gated Raman spectroscopy is demonstrated as an effective technique for the measurement of highly fluorescing Li-ion battery electrolyte materials.

Cited by 40 publications

References 39 publications

Hollow Porous α-Fe₂O₃ Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Hollow Porous α-Fe₂O₃ Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Characterising lithium-ion electrolytes via operando Raman microspectroscopy

Hollow-core optical fibre sensors for operando Raman spectroscopy investigation of Li-ion battery liquid electrolytes

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Kerr gated Raman spectroscopy of LiPF6salt and LiPF6-based organic carbonate electrolyte for Li-ion batteries

Abstract: Kerr gated Raman spectroscopy is demonstrated as an effective technique for the measurement of highly fluorescing Li-ion battery electrolyte materials.

Cited by 40 publications

References 39 publications

Hollow Porous α-Fe2O3 Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Hollow Porous α-Fe2O3 Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Characterising lithium-ion electrolytes via operando Raman microspectroscopy

Hollow-core optical fibre sensors for operando Raman spectroscopy investigation of Li-ion battery liquid electrolytes

Contact Info

Product

Resources

About

Kerr gated Raman spectroscopy of LiPF₆salt and LiPF₆-based organic carbonate electrolyte for Li-ion batteries

Hollow Porous α-Fe₂O₃ Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors

Hollow Porous α-Fe₂O₃ Nanoparticles as Anode Materials for High-Performance Lithium-Ion Capacitors