scholarly journals Novel 3D grid porous Li4Ti5O12 thick electrodes fabricated by 3D printing for high performance lithium-ion batteries

2022 ◽  
Vol 11 (2) ◽  
pp. 295-307
Author(s):  
Changyong Liu ◽  
Yin Qiu ◽  
Yanliang Liu ◽  
Kun Xu ◽  
Ning Zhao ◽  
...  

AbstractThree-dimensional (3D) grid porous electrodes introduce vertically aligned pores as a convenient path for the transport of lithium-ions (Li-ions), thereby reducing the total transport distance of Li-ions and improving the reaction kinetics. Although there have been other studies focusing on 3D electrodes fabricated by 3D printing, there still exists a gap between electrode design and their electrochemical performance. In this study, we try to bridge this gap through a comprehensive investigation on the effects of various electrode parameters including the electrode porosity, active material particle diameter, electrode electronic conductivity, electrode thickness, line width, and pore size on the electrochemical performance. Both numerical simulations and experimental investigations are conducted to systematically examine these effects. 3D grid porous Li4Ti5O12 (LTO) thick electrodes are fabricated by low temperature direct writing technology and the electrodes with the thickness of 1085 µm and areal mass loading of 39.44 mg·cm−2 are obtained. The electrodes display impressive electrochemical performance with the areal capacity of 5.88 mAh·cm−[email protected] C, areal energy density of 28.95 J·cm−[email protected] C, and areal power density of 8.04 mW·cm−[email protected] C. This study can provide design guidelines for obtaining 3D grid porous electrodes with superior electrochemical performance.

2021 ◽  
Vol 1036 ◽  
pp. 35-44
Author(s):  
Ling Fang Ruan ◽  
Jia Wei Wang ◽  
Shao Ming Ying

Silicon-based anode materials have been widely discussed by researchers because of its high theoretical capacity, abundant resources and low working voltage platform,which has been considered to be the most promising anode materials for lithium-ion batteries. However,there are some problems existing in the silicon-based anode materials greatly limit its wide application: during the process of charge/discharge, the materials are prone to about 300% volume expansion, which will resultin huge stress-strain and crushing or collapse on the anods; in the process of lithium removal, there is some reaction between active material and current collector, which creat an increase in the thickness of the solid phase electrolytic layer(SEI film); during charging and discharging, with the increase of cycle times, cracks will appear on the surface of silicon-based anode materials, which will cause the batteries life to decline. In order to solve these problems, firstly, we summarize the design of porous structure of nanometer sized silicon-based materials and focus on the construction of three-dimensional structural silicon-based materials, which using natural biomass, nanoporous carbon and metal organic framework as structural template. The three-dimensional structure not only increases the channel of lithium-ion intercalation and the rate of ion intercalation, but also makes the structure more stable than one-dimensional or two-dimensional. Secondly, the Si/C composite, SiOx composite and alloying treatment can improve the volume expansion effection, increase the rate of lithium-ion deblocking and optimize the electrochemical performance of the material. The composite materials are usually coated with elastic conductive materials on the surface to reduce the stress, increase the conductivity and improve the electrochemical performance. Finally, the future research direction of silicon-based anode materials is prospected.


NANO ◽  
2019 ◽  
Vol 14 (03) ◽  
pp. 1950037 ◽  
Author(s):  
Bingning Wang ◽  
Xuehua Liu ◽  
Binghui Xu ◽  
Yanhui Li ◽  
Dan Xiu ◽  
...  

Three-dimensional reduced graphene oxide (RGO) matrix decorated with nanoflowers of layered MoS2 (denoted as 3D MoS2/RGO) have been synthesized via a facile one-pot stepwise hydrothermal method. Graphene oxide (GO) is used as precursor of RGO and a 3D GO network is formed in the first-step of hydrothermal treatment. At the second stage of hydrothermal treatment, nanoflowers of layered MoS2 form and anchor on the surface of previously formed 3D RGO network. In this preparation, thiourea not only induces the formation of the 3D architecture at a relatively low temperature, but also works as sulfur precursor of MoS2. The synthesized composites have been investigated with XRD, SEM, TEM, Raman spectra, TGA, N2 sorption technique and electrochemical measurements. In comparison with normal MoS2/RGO composites, the 3D MoS2/RGO composite shows improved electrochemical performance as anode material for lithium-ion batteries. A high reversible capacity of 930[Formula: see text]mAh[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] after 130 cycles under a current density of 200[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] as well as good rate capability and superior cyclic stability have been observed. The superior electrochemical performance of the 3D MoS2/RGO composite as anode active material for lithium-ion battery is ascribed to its robust 3D structures, enhanced surface area and the synergistic effect between graphene matrix and the MoS2 nanoflowers subunit.


Author(s):  
Yanping Dang ◽  
Wangyu Liu ◽  
Weigui Xie ◽  
Weiping Qiu

Abstract The anode and cathode pieces are vital components of lithium-ion batteries. The coating surface density of active material is a significant parameter involved during the fabrication of electrodes and has considerable impact on battery performance. In this paper, anode and cathode pieces are prepared with different surface densities within the allowable range. The anode and cathode pieces are first graded respectively and then matched up according to different surface density ranges. Afterward, the electrodes are assembled with commercial polypropylene separator in 18,650 cell case and infused with electrolyte. The cathode is constituted with a mixture of nickel cobalt manganese (NCM) ternary material and lithium manganese oxide coated on aluminum foil, while the anode is composed of graphite coated on copper foil. The electrochemical performance and safety properties were tested to investigate the influence of the coating surface density of electrodes and optimize the electrochemical performance by regulating the matching surface density of electrodes. The results indicate that larger surface density of both cathode and anode can provide better battery consistency, while smaller surface density can contribute to better specific capacity and smaller capacity loss after cycling. Modest cost and superior properties can be achieved for lithium-ion batteries by reasonably matching the surface density of anodes and cathodes pieces.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2630 ◽  
Author(s):  
Yuyao Zhang ◽  
Jun Li ◽  
Wenyao Li ◽  
Danning Kang

TiO2 is regarded as a prospective electrode material owing to its excellent electrochemical properties such as the excellent cycling stability and the high safety. However, its low capacity and low electronic conductivity greatly restrict the further improvement in electrochemical performance. A new strategy was put forward to solve the above defects involved in TiO2 in which the low capacity was enhanced by nanomerization and porosity of TiO2, and the low electronic conductivity was improved by introducing Ag with a high conductivity. One-dimensional mesoporous Ag nanoparticles-embedded TiO2 nanofibers (Ag@TiO2 nanofibers) were successfully synthesized via a one-step electrospinning process combined with subsequent annealing treatment in this study. The microstructure and morphology of mesoporous TiO2@Ag nanofibers were confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption. TiO2 nanofibers mainly consisted of a large amount of anatase TiO2, accompanied with traces of rutile TiO2. Ag nanoparticles were uniformly distributed throughout TiO2 nanofibers and promoted the transformation of TiO2 from the anatase to the rutile. The corresponding electrochemical performances are measured by galvanostatic charge-discharge, cycle stability, rate performance, cycle voltammetry, and electrochemical impedance spectroscopy measurements in this research, with pristine TiO2 nanofibers as the reference. The results indicated that the introduction of Ag nanoparticles into TiO2 nanofibers significantly improved the diffusion coefficient of Li ions (5.42 × 10−9 cm2⋅s−1 for pristine TiO2, 1.96 × 10−8 cm2⋅s−1 for Ag@TiO2), and the electronic conductivity of TiO2 (1.69 × 10−5 S⋅cm−1 for pristine TiO2, and 1.99 × 10−5 S⋅cm−1 for Ag@TiO2), based on which the comprehensive electrochemical performance were greatly enhanced. The coulombic efficiency of the Ag@TiO2 nanofibers electrode at the first three cycles was about 56%, 93%, and 96%, which was higher than that without Ag (48%, 66%, and 79%). The Ag@TiO2 nanofibers electrode exhibited a higher specific discharge capacity of about 128.23 mAh⋅g−1 when compared with that without Ag (72.76 mAh·g−1) after 100 cycles at 100 mA·g−1. With the current density sharply increased from 40 mA·g−1 to 1000 mA·g−1, the higher average discharge capacity of 56.35 mAh·g−1 was remained in the electrode with Ag, when compared with the electrode without Ag (average discharge capacity of about 12.14 mAh·g−1). When the current density was returned to 40 mA·g−1, 80.36% of the initial value was returned (about 162.25 mAh·g−1) in the electrode with Ag, which was evidently superior to that without Ag (about 86.50 mAh·g−1, only 55.42% of the initial value). One-dimensional mesoporous Ag@TiO2 nanofibers can be regarded as a potential and promising candidate as anode materials for lithium ion batteries.


Author(s):  
Aashutosh Mistry ◽  
Daniel Juarez-Robles ◽  
Malcolm Stein ◽  
Kandler Smith ◽  
Partha P. Mukherjee

The lithium-ion battery (LIB) electrode represents a complex porous composite, consisting of multiple phases including active material (AM), conductive additive, and polymeric binder. This study proposes a mesoscale model to probe the effects of the cathode composition, e.g., the ratio of active material, conductive additive, and binder content, on the electrochemical properties and performance. The results reveal a complex nonmonotonic behavior in the effective electrical conductivity as the amount of conductive additive is increased. Insufficient electronic conductivity of the electrode limits the cell operation to lower currents. Once sufficient electron conduction (i.e., percolation) is achieved, the rate performance can be a strong function of ion-blockage effect and pore phase transport resistance. Even for the same porosity, different arrangements of the solid phases may lead to notable difference in the cell performance, which highlights the need for accurate microstructural characterization and composite electrode preparation strategies.


2020 ◽  
Author(s):  
Alain Ngandjong ◽  
Teo Lombardo ◽  
Emiliano Primo ◽  
Mehdi Chouchane ◽  
Abbos Shodiev ◽  
...  

Lithium-ion battery (LIB) manufacturing optimization is crucial to reduce its CO2 fingerprint and cost, while improving their electrochemical performance. In this article, we present an experimentally validated calendering Discrete Element Method model for LiNi0.33Mn0.33Co0.33O2–based cathodes by considering explicitly both active material (AM) and carbon-binder domain (CBD). This model was coupled to a pre-existing Coarse-Grained Molecular Dynamics model describing the slurry equilibration and its drying and a 4D-resolved Finite Element Method model for predicting electrochemical performance. Our calendering model introduces important novelties versus the state of the art, such as the utilization of un-calendered electrode mesostructures resulting from validated simulations of the slurry and drying combined with the explicit consideration of the spatial distribution and interactions between AM and CBD particles, and its validation with both experimental micro-indentation and porosity vs. calendering pressure curves. The effect of calendering on the electrode mesostructure is analyzed in terms of pore size distribution, tortuosity and particles arrangement. In addition, the evolution of the macroscopic electrochemical behavior of the electrodes upon the degree of calendering is discussed, offering added insights into the links between the calendering pressure, the electrode mesostructure and its overall performance.<br>


2019 ◽  
Author(s):  
Panpan Wang ◽  
Yue Du ◽  
Baoyou Zhang ◽  
Yanxin Yao ◽  
Yuchen Xiao ◽  
...  

The <i>β-</i>phase lithium vanadium oxide bronze (<i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub>) with high theoretic specific capacity up to 440 mAh g<sup>-1</sup> is considered as promising cathode materials, however, their practical application is hindered by its poor ionic and electronic conductivity, resulting in unsatisfied cyclic stability and rate capability. Herein, we report the surface decoration of <i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> cathode using both reduced oxide graphene and ionic conductor LaPO<sub>4</sub>, which significantly promotes the electronic transfer and Li<sup>+</sup> diffusion rate, respectively. As a result, the rGO/LaPO<sub>4</sub>/Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> composite exhibits excellent electrochemical performance in terms of high reversible specific capacity of 275.7 mAh g<sup>-1</sup> with high capacity retention of 84.1% after 100 cycles at a current density of 60 mA g<sup>-1</sup>, and acceptable specific capacity of 170.3 mAh g<sup>-1</sup> at high current density of 400 mA g<sup>-1</sup>. The cycled electrode is also analyzed by electrochemical impedance spectroscopy, <i>ex-situ </i>X-ray diffraction and scanning electron microscope, providing further insights into the improvement of electrochemical performance. Our results provide an effective approach to boost the electrochemical properties of lithium vanadates for practical application in lithium ion batteries.


Author(s):  
Erfan Moyassari ◽  
Thomas Roth ◽  
Simon Kücher ◽  
C. C. Chang ◽  
Shang-Chieh Hou ◽  
...  

Abstract One promising way of compensating for the repeated volume expansion and contraction of silicon as an anode active material in lithium ion batteries (LIBs) is to embed silicon within a graphite matrix. Silicon-graphite (SiG) composites combine the advantageous properties of graphite, i.e., large electrical conductivity and high structural stability, with the advantageous properties of silicon, i.e., high theoretical capacity. Graphite has a much lower volume expansion upon lithiation (≈ 10%) than pure silicon (≈ 300%) and provides a mechanically stable matrix. Herein, we present an investigation into the electrochemical performance and thickness change behavior of porous SiG anode compositions with silicon contents ranging from 0 wt% to 20 wt%. The electrode composites were studied using two methods: in situ dilatometry for the thickness change investigation and conventional coin cells for the assessment of electrochemical performance. The measurements show that the initial thickness change of SiG electrodes increased significantly with the silicon content, but it leveled off during cycling for all compositions. There appears to be a correlation between silicon content and capacity loss, but no clear correlation between thickness change and capacity loss rate was found.


NANO ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. 2050149
Author(s):  
Xiangyu Shi ◽  
Jifei Liu ◽  
Jianfeng Dai ◽  
Yufeng Qi

Silicon carbon nanoparticles (SCNPs) coated with reduced graphene oxide (rGO) were fabricated by a hydrothermal method and subsequently by a simple heat treatment process. SCNPs/rGO exhibit excellent electrochemical performance which not only attributes the rGO layer to inhibit the volumetric expansion of silicon and reduce the impedance between the active material and lithium ions during the electrochemical process, but also improves the electrical conductivity of SCNPs/rGO. The as-prepared compound was cyclically tested at a current density of 150[Formula: see text]mA/g, with the first charge and discharge capacities of 3152.2[Formula: see text]mAh/g and 3342.7[Formula: see text]mAh/g, respectively. Moreover, the electrochemical performance of SCNPs/rGO was better than SCNPs. The [Formula: see text] values for fresh battery, after 1 cycle and 100 cycles, are 120.9[Formula: see text][Formula: see text], 120.5[Formula: see text][Formula: see text] and 104[Formula: see text][Formula: see text]. Thus, compared with SCNPs, SCNPs/rGO exhibited lower overall impedance values. These results indicate that the addition of graphene layer significantly improved the electrochemical performance of SCNPs electrodes and reduced the internal resistance of the battery.


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