Analytical modeling of Li-ion diffusion in a three-layer electrode-separator-electrode stack with time-dependent current

<div>The electrolyte additives vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are well known for increasing the lifetime of a Li-ion battery cell by supporting the formation of an effective solid electrolyte interphase (SEI) at the anode. In this study combined simultaneous electrochemical impedance spectroscopy (EIS) and <i>operando</i> electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) are employed together with <i>in situ</i> gas analysis (OEMS) to study the influence of VC and FEC on the passivation process and the interphase properties at carbon-based anodes. In small quantities both additives reduce the initial interphase mass loading by 30 to 50 %, but only VC also effectively prevents continuous side reactions and improves anode passivation significantly. VC and FEC are both reduced at potentials above 1 V vs. Li<sup>+</sup>/Li in the first cycle and change the SEI composition which causes an increase of the SEI shear storage modulus by over one order of magnitude in both cases. As a consequence, the ion diffusion coefficient and conductivity in the interphase is also significantly affected. While small quantities of VC in the initial electrolyte increase the SEI conductivity, FEC decomposition products hinder charge transport through the SEI and thus increase overall anode impedance significantly. </div>

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Advanced ordered mesoporous carbon with fast Li-ion diffusion for lithium–selenium sulfide batteries in a carbonate-based electrolyte

Carbon ◽

10.1016/j.carbon.2020.07.039 ◽

2020 ◽

Vol 170 ◽

pp. 236-244

Author(s):

Wonhee Kim ◽

Jiyeon Lee ◽

Seungmin Lee ◽

KwangSup Eom ◽

Chanho Pak ◽

...

Keyword(s):

Mesoporous Carbon ◽

Ordered Mesoporous Carbon ◽

Ion Diffusion ◽

Ordered Mesoporous ◽

Li Ion ◽

Selenium Sulfide

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Influence of Structural Distortion and Lattice Dynamics on Li-Ion Diffusion in Li3OCl1–xBrx Superionic Conductors

ACS Applied Energy Materials ◽

10.1021/acsaem.0c02519 ◽

2021 ◽

Author(s):

Ronghan Chen ◽

Zhenming Xu ◽

Yuechuan Lin ◽

Buyao Lv ◽

Shou-Hang Bo ◽

...

Keyword(s):

Lattice Dynamics ◽

Structural Distortion ◽

Superionic Conductors ◽

Ion Diffusion ◽

Li Ion

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Effect of Li Source on Charge/Discharge Performance of LiFePO4

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.509.51 ◽

2012 ◽

Vol 509 ◽

pp. 51-55

Author(s):

Hong Quan Liu ◽

Fei Xiang Hao ◽

Yi Jie Gu ◽

Yun Bo Chen

Keyword(s):

Low Cost ◽

Utilization Efficiency ◽

Ion Diffusion ◽

Diffusion Distance ◽

Pore Characteristics ◽

Discharge Performance ◽

High Theoretical Capacity ◽

Low Toxicity ◽

Li Ion ◽

Potential Plateau

LiFePO4 has been considered as the most promising positive electrode due to its low cost, high theoretical capacity, stability and low toxicity, all highly required in vehicle applications. In this work, LiFePO4 compound was synthesized by the solid carbothermic reduction reactions with different Li resource. The pure LiFePO4 phase was confirmed for all samples by analysis of the XRD results. The different morphologies were obtained due to different Li resources. The potential plateau of all samples is in the range from 3V to 4V. The sample (LiCO3 as the Li resource) has a higher discharge capacity of 118mAhg−1 at 0.2C 20% greater than that of the sample (LiOH as the Li resource). The reason comes maybe from nano pore characteristics, which reduce Li ion diffusion distance, and increase the utilization efficiency of material.

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Synthesis and Electrochemical Properties of Spherical LiFePO4/C Composite via Spray Drying

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1120-1121.554 ◽

2015 ◽

Vol 1120-1121 ◽

pp. 554-558 ◽

Cited By ~ 1

Author(s):

Juan Mei Wang ◽

Bing Ren ◽

Ying Lin Yan ◽

Qing Zhang ◽

Yan Wang

Keyword(s):

Diffusion Coefficient ◽

Electrochemical Properties ◽

Spray Drying ◽

Electrochemical Impedance ◽

Retention Rate ◽

Lithium Ion ◽

Constant Current ◽

Ion Diffusion ◽

Electrochemical Tests ◽

Li Ion

In this work, spherical LiFePO4/C composite had been synthesized by co-precipitation and spray drying method. The structure, morphology and electrochemical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), transmission electron microscope (TEM), constant current charge-discharge tests and electrochemical impedance spectroscopy (EIS) tests. The spherical LiFePO4/C particles consisted of a number of smaller grains. The results showed that the morphology of LiFePO4/C particles seriously affected the Li-ion diffusion coefficient and electrochemical properties of lithium ion batteries. Electrochemical tests revealed the spherical LiFePO4/C composite had excellent Li-ion diffusion coefficient which was calculated to be 1.065×10-11 cm2/s and discharge capacity of 149 (0.1 C), 139 (0.2 C), 133 (0.5 C), 129 (1 C) and 124 mAhg-1(2 C). After 50 cycles, the capacity retention rate was still 93.5%.

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