Role of precursor chemistry in the direct fluorination to form titanium based conversion anodes for lithium ion batteries

Powell, Jonathan M.; Adcock, James L.; Dai, Sheng; Veith, Gabriel M.; Bridges, Craig A.

doi:10.1039/c5ra17258f

Cited by 15 publications

(24 citation statements)

References 81 publications

(169 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This relatively high BE peak can also be argued to be specifically related to TiF 3 , which is electrochemically active . The FMX6 and FMX24 samples show Ti spectra containing peaks from only Ti 4+ , which was shown to be from the compound TiOF 2 . The Ti spectra confirm the absence of Ti−C bonds in FMX6 and FMX24 and show the formation of TiOF 2 on these samples.…”

Section: Resultsmentioning

confidence: 85%

“…In addition, weak TiO 2 peaks were observed in this pattern, which do not change during F 2 anneal. The partial fluorination of trace TiO 2 impurities in the starting powder would have a minimal overall effect of the mass gain observed, and in fact the 150 °C temperature is too low to effect full conversion to TiOF 2 . The weak, sharp peaks at 2 θ ≈9.7 and 19.4° are the (0 0 2) and (0 0 4) reflections from the Ti 3 AlC 2 phase, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…After 6 h fluorination, given that TiF 3 is not observed in the XRD patterns (Figure ), we may expect that much of the TiF 3 is converted to TiF 4 (

T i {normalF}_{3} + 1 / 2 {normalF}_{2} \to T i {normalF}_{4}

), which can sublimate. In the presence of oxygen TiOF 2 forms, becoming the dominant species on the surface for samples FMX6 and FMX24 as exemplified by the XRD and XPS results in Figures and . It is evident from the micrographs in Figure that MXene consists of exfoliated layers, and that after fluorination these layers do not collapse.…”

Section: Resultsmentioning

confidence: 99%

“…This indicates that FMX6 does not have a good rate capability. FMX24 is more pseudo‐rectangular with broad anodic/cathodic peaks at approximately 1.2/0.9 V. These peaks are consistent with the reported discharge/charge profiles for TiO 2 fluorinated to form TiOF 2 . Considering that MXene, FMX3, and FMX6 have semi‐ionic C−F bonds (see Figure c), the anodic/cathodic peaks at approximately 1.1/0.9 V could be a result of these bonds reversibly converting to ionic bonds by interacting with Li.…”

Section: Resultsmentioning

confidence: 99%

“…Fluorination has drawn attention as a tool for post‐processing to modify materials for enhanced properties in different applications . There are several methods of fluorinating materials, such as the wet chemical method, in which the material is dispersed and reacted with a fluorinated solution (i.e., HF, NH 4 HF 2 , etc.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

et al. 2019

Self Cite

View full text Add to dashboard Cite

What prompted you to investigate this topic/problem? Lithium-ion batteries (LIBs), due to the inherentl imitations of traditional electrode materials, have relatively low energy and power density which hinders their application for electric vehicles. In order to tackle this problem, different engineering routes are being developed to increase their performance. Therefore, we have developed ad irect-fluorination process for the formation of oxyfluorides with the aim of also improving the cost effectiveness and practicality.D irect fluorination by elemental fluorine is one of the best solutions to obtain highly pure oxyfluoride materials, whicho ur group is using for research on electrode materials. With this approach, we have demonstrated for the first time the formation of 2D-titanium oxyfluoride (TiOF 2 )v ia low temperature directfluorination.

show abstract

Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 99%

“…After 6 h fluorination, given that TiF 3 is not observed in the XRD patterns (Figure ), we may expect that much of the TiF 3 is converted to TiF 4 (

T i {normalF}_{3} + 1 / 2 {normalF}_{2} \to T i {normalF}_{4}

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

Fluorine Functionalized MXene QDs for Near‐Record‐Efficiency CsPbI₃ Solar Cell with High Open‐Circuit Voltage

Han

et al. 2022

Adv Funct Materials

View full text Add to dashboard Cite

CsPbI 3 inorganic perovskites have attracted significant attention due to their desirable bandgap for tandem solar cells and excellent thermal stability. However, CsPbI 3 perovskite solar cells (PSCs) still exhibit low efficiency and high energy loss due to nonradiative recombination. Herein, functionalized Ti 3 C 2 F x quantum dots (QDs) are prepared and selected as interface passivators to enhance the performance of CsPbI 3 PSCs. The systematic experimental results reveal that Ti 3 C 2 F x QDs serve as effective passivators mainly in three aspects: 1) p-type Ti 3 C 2 F x QDs can tune the energy level of perovskite films and provide an efficient pathway for hole transfer; 2) Ti 3 C 2 F x QDs can effectively passivate defects and reduce interfacial nonradiative recombination, and 3) Ti 3 C 2 F x QDs form a barrier layer to prevent water invasion and improve the stability of CsPbI 3 PSCs. Consequently, the champion CsPbI 3 PSC with Ti 3 C 2 F x QDs treatment exhibits an excellent efficiency of 20.44% with a high open-circuit voltage of 1.22 V. Meanwhile, the corresponding device without encapsulation retained 93% of its initial efficiency after 600 h of storage in ambient air.

show abstract

Enhancing Cycling Stability and Capacity Retention of NMC811 Cathodes by Reengineering Interfaces via Electrochemical Fluorination

Thapaliya

Misra

Yang

et al. 2022

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

ranging from 140 to 200 mAh g −1 , which is the capacity limiting electrode that determines the energy density of a cell. Therefore, it is essential to develop high-energy-density cathode materials with long cycling stability and high capacity retention for the longer driving ranges that promote vehicle electrification.To revolutionize electromobility, extensive research is being carried out on the high-capacity cathodes, amongst other cell components, with new approaches identified to optimize their performances. [4][5][6] LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811 (80% Ni)) is one of the most promising cathode materials and has been touted as the next generation high capacity cathode for vehicle electrification because of its low Co content and simultaneous high practical energy density (specific capacity of ≈200 mAh g −1 and high discharge potential of ≈3.8 V vs Li/Li + ), [7][8][9] rate capability, and relatively lower cost. However, these high-energy cathodes with higher Ni content have suffered from structural instability, rapid capacity fading, and voltage evolution upon cycling. The instability of high voltage, high capacity cathodes originates from the reversible/irreversible phase transitions, particle cracking, oxygen evolution, transition metal cation dissolution, and detrimental side reactions with electrolytes at the electrode-electrolyte interphase leading to thick cathode-electrolyte interphase (CEI). [10][11][12][13][14][15] Similarly, the rapid capacity fading of NMC811, when cycled High-capacity cathodes (LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) that can boost the energy density of lithium-ion batteries are promising candidates for vehicle electrification. However, several factors specific to high energy density materials entailing electrode reactions inhibit their application. Fluorination has shown a promising ability to combat the detrimental electrochemical performances of cathode materials, however, it remains difficult to achieve the desired functionality. Herein, a novel electrochemical fluorination (ECF) that demonstrates a promising electrochemical performance enhancement via stabilization of the cathode-electrolyte-interphase (CEI) by forming conformal LiF is proposed. Besides LiF surface layer formation, ECF reduces the degree of fluorinationinduced Ni/Li disordering and enhances the layered structural stability as probed by X-ray diffraction. Because of the robust CEI, ECF-NMC811 cathodes deliver 203.0 mAh g −1 first discharge capacity at the current rate of C/10, with ≈98% capacity retention up to 100 cycles. Similarly, it delivers ≈180 mAh g −1 capacity at a 1 C rate with 86.4% capacity retention up to 200 cycles with average coulombic efficiency of > 99.5%. Comprehensive characterization with a multitude of probes reveals that ECF enhances the cycling stability of the electrode without altering bulk structure and morphology.

show abstract

Role of precursor chemistry in the direct fluorination to form titanium based conversion anodes for lithium ion batteries

Abstract: An effective approach to increasing the reversible specific capacity of TiOF2 conversion electrodes is presented. The capacity increased greatly when the precursor was partially reduced before direct fluorination in a fluidized bed reactor.

Cited by 15 publications

References 81 publications

Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

Fluorine Functionalized MXene QDs for Near‐Record‐Efficiency CsPbI₃ Solar Cell with High Open‐Circuit Voltage

Enhancing Cycling Stability and Capacity Retention of NMC811 Cathodes by Reengineering Interfaces via Electrochemical Fluorination

Contact Info

Product

Resources

About

Role of precursor chemistry in the direct fluorination to form titanium based conversion anodes for lithium ion batteries

Abstract: An effective approach to increasing the reversible specific capacity of TiOF2 conversion electrodes is presented. The capacity increased greatly when the precursor was partially reduced before direct fluorination in a fluidized bed reactor.

Cited by 15 publications

References 81 publications

Fluorination of MXene by Elemental F2 as Electrode Material for Lithium‐Ion Batteries

Fluorination of MXene by Elemental F2 as Electrode Material for Lithium‐Ion Batteries

Fluorine Functionalized MXene QDs for Near‐Record‐Efficiency CsPbI3 Solar Cell with High Open‐Circuit Voltage

Enhancing Cycling Stability and Capacity Retention of NMC811 Cathodes by Reengineering Interfaces via Electrochemical Fluorination

Contact Info

Product

Resources

About

Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

Fluorine Functionalized MXene QDs for Near‐Record‐Efficiency CsPbI₃ Solar Cell with High Open‐Circuit Voltage