Cycling-induced structural damage/degradation of electrode materials – microscopic viewpoint

Nanotechnology ◽

10.1088/1361-6528/ac3616 ◽

2021 ◽

Author(s):

Fuqian Yang

Keyword(s):

Intermetallic Compounds ◽

Structural Damage ◽

Electrode Materials ◽

Crack Tip ◽

Lithium Ion ◽

Simple Calculation ◽

Radius Of Curvature ◽

Critical Separation ◽

Analytical Formulas ◽

Body Potential

Abstract Most analyses of the mechanical deformation of electrode materials of lithium-ion battery in the framework of continuum mechanics suggest the occurring of structural damage/degradation during the de-lithiation phase and cannot explain the lithiation-induced damage/degradation in electrode materials, as observed experimentally. In this work, we present first-principle analysis of the interaction between two adjacent silicon atoms from the Stillinger-Weber two-body potential and obtain the critical separation between the two silicon atoms for the rupture of Si-Si bonds. Simple calculation of the engineering-tensile strain for the formation of Li-Si intermetallic compounds from the lithiation of silicon reveals that cracking and cavitation in lithiated silicon can occur due to the formation of Li-Si intermetallic compounds. Assuming the proportionality between the net mass flux across the tip surface of a slit crack and the migration rate of the crack tip, we develop analytical formulas for the growth and healing of the slit crack controlled by lithiation and de-lithiation, respectively. It is the combinational effects of the state of charge, the radius of curvature of the crack tip and local electromotive force that determine the cycling-induced growth and healing of surface cracks in lithiated silicon.

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Self-assembly Nb2O5 microsphere with hollow and carbon coated structure as high rate capability lithium-ion electrode materials

Electrochimica Acta ◽

10.1016/j.electacta.2019.135364 ◽

2020 ◽

Vol 331 ◽

pp. 135364 ◽

Cited By ~ 5

Author(s):

Jiajun Hu ◽

Jiajia Li ◽

Kai Wang ◽

Hongyan Xia

Keyword(s):

Self Assembly ◽

Electrode Materials ◽

Rate Capability ◽

Lithium Ion ◽

High Rate ◽

High Rate Capability ◽

Carbon Coated

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A Segregated Approach for Modeling the Electrochemistry in the 3-D Microstructure of Li-Ion Batteries and Its Acceleration Using Block Preconditioners

Journal of Scientific Computing ◽

10.1007/s10915-021-01410-5 ◽

2021 ◽

Vol 86 (3) ◽

Author(s):

Jeffery M. Allen ◽

Justin Chang ◽

Francois L. E. Usseglio-Viretta ◽

Peter Graf ◽

Kandler Smith

Keyword(s):

Degrees Of Freedom ◽

Electrode Materials ◽

Lithium Ion ◽

Automotive Application ◽

System Of Equations ◽

Strongly Correlated ◽

Electrolyte Depletion ◽

Li Ion ◽

Block Preconditioners ◽

Electrochemical Model

AbstractBattery performance is strongly correlated with electrode microstructure. Electrode materials for lithium-ion batteries have complex microstructure geometries that require millions of degrees of freedom to solve the electrochemical system at the microstructure scale. A fast-iterative solver with an appropriate preconditioner is then required to simulate large representative volume in a reasonable time. In this work, a finite element electrochemical model is developed to resolve the concentration and potential within the electrode active materials and the electrolyte domains at the microstructure scale, with an emphasis on numerical stability and scaling performances. The block Gauss-Seidel (BGS) numerical method is implemented because the system of equations within the electrodes is coupled only through the nonlinear Butler–Volmer equation, which governs the electrochemical reaction at the interface between the domains. The best solution strategy found in this work consists of splitting the system into two blocks—one for the concentration and one for the potential field—and then performing block generalized minimal residual preconditioned with algebraic multigrid, using the FEniCS and the Portable, Extensible Toolkit for Scientific Computation libraries. Significant improvements in terms of time to solution (six times faster) and memory usage (halving) are achieved compared with the MUltifrontal Massively Parallel sparse direct Solver. Additionally, BGS experiences decent strong parallel scaling within the electrode domains. Last, the system of equations is modified to specifically address numerical instability induced by electrolyte depletion, which is particularly valuable for simulating fast-charge scenarios relevant for automotive application.

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Nitrogen-enriched graphene framework from a large-scale magnesiothermic conversion of CO2 with synergistic kinetics for high-power lithium-ion capacitors

NPG Asia Materials ◽

10.1038/s41427-021-00327-7 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Chen Li ◽

Xiong Zhang ◽

Kai Wang ◽

Xianzhong Sun ◽

Yanan Xu ◽

...

Keyword(s):

Energy Density ◽

High Power ◽

Power Output ◽

Large Scale ◽

Electrode Materials ◽

Lithium Ion ◽

High Energy ◽

High Energy Density ◽

Chemical Doping ◽

Lithium Ion Capacitor

AbstractLithium-ion capacitors are envisaged as promising energy-storage devices to simultaneously achieve a large energy density and high-power output at quick charge and discharge rates. However, the mismatched kinetics between capacitive cathodes and faradaic anodes still hinder their practical application for high-power purposes. To tackle this problem, the electron and ion transport of both electrodes should be substantially improved by targeted structural design and controllable chemical doping. Herein, nitrogen-enriched graphene frameworks are prepared via a large-scale and ultrafast magnesiothermic combustion synthesis using CO2 and melamine as precursors, which exhibit a crosslinked porous structure, abundant functional groups and high electrical conductivity (10524 S m−1). The material essentially delivers upgraded kinetics due to enhanced ion diffusion and electron transport. Excellent capacities of 1361 mA h g−1 and 827 mA h g−1 can be achieved at current densities of 0.1 A g−1 and 3 A g−1, respectively, demonstrating its outstanding lithium storage performance at both low and high rates. Moreover, the lithium-ion capacitor based on these nitrogen-enriched graphene frameworks displays a high energy density of 151 Wh kg−1, and still retains 86 Wh kg−1 even at an ultrahigh power output of 49 kW kg−1. This study reveals an effective pathway to achieve synergistic kinetics in carbon electrode materials for achieving high-power lithium-ion capacitors.

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A novel eutectic solvent precursor for efficiently preparing N-doped hierarchically porous carbon nanosheets with unique surface functional groups and micro-pores towards dual-carbon lithium-ion capacitors

Journal of Materials Chemistry A ◽

10.1039/d1ta03071j ◽

2021 ◽

Author(s):

Kaixiang Zou ◽

Yuanfu Deng ◽

Weijing Wu ◽

Shiwei Zhang ◽

Guohua Chen

Keyword(s):

Functional Groups ◽

Porous Carbon ◽

High Performance ◽

Electrode Materials ◽

Lithium Ion ◽

Surface Functional Groups ◽

Carbon Nanosheets ◽

Hierarchically Porous ◽

Li Ion ◽

Unique Surface

High performance carbon-based materials are ideal electrode materials for Li-ion capacitors (LICs), but there are still many challenges such as the complicated preparation preocesses, high cost and low yield. Also,...

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Advances in the Applications of Graphene-Based Nanocomposites in Clean Energy Materials

Crystals ◽

10.3390/cryst11010047 ◽

2021 ◽

Vol 11 (1) ◽

pp. 47

Author(s):

Yiqiu Xiang ◽

Ling Xin ◽

Jiwei Hu ◽

Caifang Li ◽

Jimei Qi ◽

...

Keyword(s):

Solar Cells ◽

Fuel Cells ◽

Lithium Ion Batteries ◽

Electrode Materials ◽

Specific Capacity ◽

Lithium Ion ◽

Clean Energy ◽

Proton Exchange ◽

Energy Storage And Conversion ◽

Thermoelectric Conversion

Extensive use of fossil fuels can lead to energy depletion and serious environmental pollution. Therefore, it is necessary to solve these problems by developing clean energy. Graphene materials own the advantages of high electrocatalytic activity, high conductivity, excellent mechanical strength, strong flexibility, large specific surface area and light weight, thus giving the potential to store electric charge, ions or hydrogen. Graphene-based nanocomposites have become new research hotspots in the field of energy storage and conversion, such as in fuel cells, lithium-ion batteries, solar cells and thermoelectric conversion. Graphene as a catalyst carrier of hydrogen fuel cells has been further modified to obtain higher and more uniform metal dispersion, hence improving the electrocatalyst activity. Moreover, it can complement the network of electroactive materials to buffer the change of electrode volume and prevent the breakage and aggregation of electrode materials, and graphene oxide is also used as a cheap and sustainable proton exchange membrane. In lithium-ion batteries, substituting heteroatoms for carbon atoms in graphene composite electrodes can produce defects on the graphitized surface which have a good reversible specific capacity and increased energy and power densities. In solar cells, the performance of the interface and junction is enhanced by using a few layers of graphene-based composites and more electron-hole pairs are collected; therefore, the conversion efficiency is increased. Graphene has a high Seebeck coefficient, and therefore, it is a potential thermoelectric material. In this paper, we review the latest progress in the synthesis, characterization, evaluation and properties of graphene-based composites and their practical applications in fuel cells, lithium-ion batteries, solar cells and thermoelectric conversion.

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Preparation of LiFePO4 Powders by Ultrasonic Spray Drying Method and Their Memory Effect

Materials ◽

10.3390/ma14123193 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3193

Author(s):

Tu Lan ◽

Xiaolong Guo ◽

De Li ◽

Yong Chen

Keyword(s):

Spray Drying ◽

Memory Effect ◽

Electrode Materials ◽

Average Particle Size ◽

Lithium Ion ◽

Average Particle ◽

Preparation Process ◽

Drying Method ◽

Drying Temperature ◽

Ultrasonic Spray

The memory effect of lithium-ion batteries (LIBs) was first discovered in LiFePO4, but its origin and dependence are still not clear, which is essential for regulating the memory effect. In this paper, a home-made spray drying device was used to successfully synthesize LiFePO4 with an average particle size of about 1 μm, and we studied the influence of spray drying temperature on the memory effect of LiFePO4 in LIBs. The results showed that the increasing of spray drying temperature made the memory effect of LiFePO4 strengthen from 1.3 mV to 2.9 mV, while the capacity decreased by approximately 6%. The XRD refinement and FTIR spectra indicate that the enhancement of memory effect can be attributed to the increment of Li–Fe dislocations. This work reveals the dependence of memory effect of LiFePO4 on spray drying temperature, which will guide us to optimize the preparation process of electrode materials and improve the management system of LIBs.

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Engineering flexible carbon nanofibers concatenated MOFs-derived hollow octahedral CoFe2O4 as anode materials for enhanced lithium storage

Inorganic Chemistry Frontiers ◽

10.1039/d1qi00414j ◽

2021 ◽

Author(s):

Fangfang Xue ◽

Yangyang Li ◽

Chen Liu ◽

Zhigang Zhang ◽

Jun Lin ◽

...

Keyword(s):

Mechanical Property ◽

Anode Materials ◽

Electrode Materials ◽

Electronic Devices ◽

High Capacity ◽

Lithium Ion ◽

Lithium Storage ◽

Excellent Mechanical Property ◽

Wearable Electronic ◽

Wearable Electronic Devices

Constructing suitable electrode materials with high capacity and excellent mechanical property is indispensable for flexible lithium-ion batteries (LIBs) to satisfy the growing flexible and wearable electronic devices. Herein, a necklace-like...

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