Diffusion-limited C-rate: A criterion of rate performance for lithium-ion batteries

Zuo, Anhao; Fang, Ruqing; Wu, Zhixuan; Li, Zhe

doi:10.1016/j.est.2022.105920

Cited by 11 publications

(5 citation statements)

References 29 publications

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“…However, this phenomenon is reversed at high current rates starting at 1 C. Notably, at 2 C, the specific capacities of NMC622 with low and high porosity are 27.2 mAh g and 94.1 mAh g −1 , respectively, showing a higher difference in specific capacities. For high C-rates, the capacity of the Li-ion of the NMC622 electrode is significantly reduced due to the rate-limiting Li-ion transport process in the electrolyte, this observation was also reported by Zuo et al 16 Figure 1b shows the discharge capacities (lithiation) of NMC622.…”

Section: Resultssupporting

confidence: 81%

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

Alolaywi,

Uzun,

Cheng

2024

J. Electrochem. Soc.

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LiNi0.6Mn0.2Co0.2O2 (NMC622) is a widely used positive electrode material for lithium-ion batteries, including electric vehicles. In this work, we investigated the effects of porosity, ranging from “zero” to the typical 35%, on the electrochemical behavior of high-loading NMC622 electrodes. Although it is well known that the energy density of the electrode increases with increasing areal capacity and decreasing porosity, NMC-positive electrodes with exceedingly low porosity (e.g., near zero) and high loading (e.g., 4 mAh cm-2) have not been investigated. Here, we report an intriguing observation that the “zero porosity” NMC electrode can have higher capacity at low C-rates, and the volumetric energy density significantly increases to 1739 Wh L-1 compared to 805 Wh L-1 of conventional electrodes of 35% porosity. We performed cyclic voltammetry and electrochemical impedance spectroscopy to help understand this observation. This work provides new insights into the effects of porosity on the electrochemical behavior of high-loading positive electrodes.

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Section: Resultssupporting

confidence: 81%

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

Alolaywi,

Uzun,

Cheng

2024

J. Electrochem. Soc.

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“…The trend of decreasing capacity with increasing C rate agrees with those described elsewhere for uniform composition electrodes. 36,37 By examining similar plots to those shown in Figs. 4 to 7 (not shown for brevity), the progressive drop in discharge capacity was identified as principally due to Li concentration depletion in the electrolyte in the LFP sub-layer close to the current collector, leading to under utilization of some of the LFP, as well as NMC, particles.…”

Section: Resultsmentioning

confidence: 96%

A Multilayer Doyle-Fuller-Newman Model to Optimise the Rate Performance of Bilayer Cathodes in Li Ion Batteries

Tredenick,

Wheeler,

Drummond

et al. 2024

J. Electrochem. Soc.

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Bilayer cathodes comprising two active materials are explored for their ability to improve lithium-ion battery charging performance. Electrodes are manufactured with various arrangements of lithium nickel manganese cobalt oxide Li[Ni0.6Co0.2Mn0.2]O2 (NMC622) and lithium iron phosphate LiFePO4 (LFP) active particles, including in two different discrete sub-layers. We present experimental data on the sensitivity of the electrode C rate performance to the electrode design. To understand the complex bilayer electrode performance, and to identify an optimal design for fast charging, we develop an extension to the Doyle-Fuller-Newman (DFN) model of electrode dynamics that accommodates different active materials in any number of sub-layers, termed the multilayer DFN (M-DFN) model. The M-DFN model is validated against experimental data and then used to explain the performance differences between the electrode arrangements. We show how the different open circuit potential functions of NMC and LFP can be exploited synergistically through electrode design. Manipulating the Li electrolyte concentration increases achievable capacity. Finally the M-DFN model is used to further optimize the best performing bilayer electrode arrangement by adjusting the ratio of the LFP and NMC sub-layer thickness.

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“…At first glance, it was clear that the cell containing the PVDF-HFP- g -PSSA binder material showed a noteworthy enhancement in discharge capacity compared to the cell containing the PVDF binder. Furthermore, due to the constrained diffusion of lithium ion in cathode active materials at high current densities, the capacity dwindles . The half-cells made of LiFePO 4 /carbon black as active material and PVDF as binding agent displayed maximum initial capacity of 232 mAh g –1 at 0.1 C and also lower capacities of 216, 190, 73, and 37 mAh g –1 at higher current densities of 0.2 0.5, 1, and 3 C, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, due to the constrained diffusion of lithium ion in cathode active materials at high current densities, the capacity dwindles. 56 The half-cells made of LiFePO 4 /carbon black as active material and PVDF as binding agent displayed maximum initial capacity of 232 mAh g −1 at 0.1 C and also lower capacities of 216, 190, 73, and 37 mAh g −1 at higher current densities of 0.2 0.5, 1, and 3 C, respectively. However, the electrodes that included PVDF-HFP-g-PSSA as a binding agent demonstrated higher discharge capacities of 340, 313, 286, 261, and 195 mAh g −1 at 0.1 0.2, 0.5, 1, and 3 C, respectively.…”

Section: Electrochemicalmentioning

confidence: 92%

The Effect of Poly(vinylidene difluoride-co-hexafluoropropylene)-g-poly(styrene sulfonate) Binder and Carbon Fiber Current Collector on the Electrochemical Performance of LiFePO₄ Cathode for Lithium-Ion Batteries

Gorji,

Ghahramani,

Haghighi-Yazdi

2024

ACS Appl. Energy Mater.

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The current investigation explores the influence of the poly(vinylidene fluoride-co-hexafluoropropylene)-graf t-poly-(sodium styrenesulfonate) (PVDF-HFP-g-PSSA) binder on the electrochemical performance of LiFePO 4 electrodes using electrochemical measurements of cathodic half-cells. A comparison is made between the electrochemical enhancements of the brush copolymer synthesized by using the atom transfer radical polymerization (ATRP) process and the traditional PVDF binder material. Substituting conventional aluminum current collectors with carbon fiber current collectors effectively enhances the active surface area of the electrodes. The outcomes of the research illustrate that the utilization of the PVDF-HFP-g-PSSA binder leads to reduced concentration polarization and boosted intercalation kinetics, particularly at higher cycle numbers. The cathode comprising the PVDF-HFP-g-PSSA copolymer binder displays a remarkably high initial discharge capacity value of 340 mAh g −1 when subjected to a 0.1 C current density. Additionally, after 300 charge/discharge cycles, a discharge capacity value of 143 mAh g −1 is observed at 0.5 C. Furthermore, the initial capacity at 3 C is 195 mAh g −1 and reaches 160 mAh g −1 after 100 cycles. It is noteworthy that the Coulombic efficiency of this cathode is 100% even after 300 cycles. The synergistic impact of utilizing carbon fibers and sulfonated binders can enhance the potential of structural batteries over conventional lithium-ion batteries (LIBs), enabling them to be used for high-efficiency battery designs suitable for electric vehicles.

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Diffusion-limited C-rate: A criterion of rate performance for lithium-ion batteries

Cited by 11 publications

References 29 publications

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

A Multilayer Doyle-Fuller-Newman Model to Optimise the Rate Performance of Bilayer Cathodes in Li Ion Batteries

The Effect of Poly(vinylidene difluoride-co-hexafluoropropylene)-g-poly(styrene sulfonate) Binder and Carbon Fiber Current Collector on the Electrochemical Performance of LiFePO₄ Cathode for Lithium-Ion Batteries

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Diffusion-limited C-rate: A criterion of rate performance for lithium-ion batteries

Cited by 11 publications

References 29 publications

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

A Multilayer Doyle-Fuller-Newman Model to Optimise the Rate Performance of Bilayer Cathodes in Li Ion Batteries

The Effect of Poly(vinylidene difluoride-co-hexafluoropropylene)-g-poly(styrene sulfonate) Binder and Carbon Fiber Current Collector on the Electrochemical Performance of LiFePO4 Cathode for Lithium-Ion Batteries

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The Effect of Poly(vinylidene difluoride-co-hexafluoropropylene)-g-poly(styrene sulfonate) Binder and Carbon Fiber Current Collector on the Electrochemical Performance of LiFePO₄ Cathode for Lithium-Ion Batteries