scholarly journals Mechanical Integrity of Conductive Carbon-Black-Filled Aqueous Polymer Binder in Composite Electrode for Lithium-Ion Battery

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1460
Author(s):  
Kehua Peng ◽  
Yaolong He ◽  
Hongjiu Hu ◽  
Shufeng Li ◽  
Bao Tao
Keyword(s):  
Carbon Black ◽  
Composite Electrode ◽  
Mechanical Stability ◽  
Critical Role ◽  
Active Material ◽  
Mechanical Damage ◽  
Lithium Ion ◽  
Spherical Particles ◽  
Inorganic Filler ◽  
Composite Electrodes

The mechanical stability of aqueous binder and conductive composites (BCC) is the basis of the long-term service of composite electrodes in advanced secondary batteries. To evaluate the stress evolution of BCC in composite electrodes during electrochemical operation, we established an electrochemical–mechanical model for multilayer spherical particles that consists of an active material and a solid-electrolyte-interface (SEI)-enclosed BCC. The lithium-diffusion-induced stress distribution was studied in detail by coupling the influence of SEI and the viscoelasticity of inorganic-filler-doped polymeric bonding material. It was found that tensile hoop stress plays a critical role in determining whether a composite electrode is damaged or not—and circumferential cracks may primarily initiate in BCC, rather than in other electrode components. Further, the peak tensile stress of BCC is at the interface with SEI and does not occur at full lithiation due to the relaxation nature of polymer composite. Moreover, mechanical damage would be greatly misled if neglecting the existence of SEI. Finally, the structure integrity of the binder and conductive system can be effectively improved by (1) increasing the carbon black content as much as possible in the context of meeting cell capacity requirements—it is greater than 27% and 50% for sodium alginate and the mixtures of carboxy styrene butadiene latex and sodium carboxymethyl cellulose, respectively, for composite graphite anode; (2) reducing the elastic modulus of SEI to less than that of BCC; (3) decreasing the lithiation rate.

scholarly journals Sodium Induced Morphological Changes of Carbon Coated TiO2 Anatase Nanoparticles – High-Performance Materials for Na-Ion Batteries

MRS Advances ◽  
2020 ◽  
Vol 5 (43) ◽  
pp. 2221-2229
Author(s):  
G. Greco ◽  
S. Passerini
Keyword(s):  
Large Scale ◽  
Morphological Changes ◽  
Low Cost ◽  
Cell Structure ◽  
Active Material ◽  
Lithium Ion ◽  
Composite Electrodes ◽  
Carbon Coated ◽  
Anatase Nanoparticles ◽  
First Time

AbstractThe most promising candidate as an everyday alternative to lithium-ion batteries (LIBs) are sodium-ion batteries (NIBs). This is not only due to Na abundance, but also because the main principles and cell structure are very similar to LIBs. Due to these benefits, NIBs are expected to be used in applications related to large-scale energy storage systems and other applications not requiring top-performance in terms of volumetric capacity. One important issue that has hindered the large scale application of NIBs is the anode material. Graphite and silicon, which have been widely applied as anodes in NIBs, do not show great performance. Hard carbons look very promising in terms of their abundance and low cost, but they tend to suffer from instability, in particular over the long term. In this work we explore a carbon-coated TiO2 nanoparticle system that looks very promising in terms of stability, abundance, low-cost, and most importantly that safety of the cell, since it does not suffer from potential sodium plating during cycling. Maintaining a nano-size and consistent morphology of the active material is a crucial parameter for maintaining a well-functioning cell upon cycling. In this work we applied Anomalous Small Angle X-Ray Scattering (ASAXS) for the first time at the Ti K-edge of TiO2 anatase nanoparticles on different cycled composite electrodes in order to have a complete morphological overview of the modifications induced by sodiation and desodiation. This work also demonstrates for the first time that the nanosize of the TiO2 is maintained upon cycling, which is in agreement with the electrochemical stability.

scholarly journals Applications of Long-Length Carbon Nano-Tube (L-CNT) as Conductive Materials in High Energy Density Pouch Type Lithium Ion Batteries

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1471
Author(s):  
Shan-Ho Tsai ◽  
Ying-Ru Chen ◽  
Yi-Lin Tsou ◽  
Tseng-Lung Chang ◽  
Hong-Zheng Lai ◽  
...  
Keyword(s):  
Energy Density ◽  
Carbon Black ◽  
Active Material ◽  
Lithium Ion ◽  
High Energy ◽  
Positive Electrode ◽  
High Energy Density ◽  
High Resistivity ◽  
Portable Devices ◽  
Carbon Nano Tube

Lots of lithium ion battery (LIB) products contain lithium metal oxide LiNi5Co2Mn3O2 (LNCM) as the positive electrode’s active material. The stable surface of this oxide results in high resistivity in the battery. For this reason, conductive carbon-based materials, including acetylene black and carbon black, become necessary components in electrodes. Recently, carbon nano-tube (CNT) has appeared as a popular choice for the conductive carbon in LIB. However, a large quantity of the conductive carbon, which cannot provide capacity as the active material, will decrease the energy density of batteries. The ultra-high cost of CNT, compared to conventional carbon black, is also a problem. In this work, we are going to introduce long-length carbon nano-tube s(L-CNT) into electrodes in order to design a reduced-amount conductive carbon electrode. The whole experiment will be done in a 1Ah commercial type pouch LIB. By decreasing conductive carbon as well as increasing the active material in the positive electrode, the energy density of the LNCM-based 1Ah pouch type LIB, with only 0.16% of L-CNT inside the LNCM positive electrode, could reach 224 Wh/kg and 549 Wh/L, in weight and volume energy density, respectively. Further, this high energy density LIB with L-CNT offers stable cyclability, which may constitute valuable progress in portable devices and electric vehicle (EV) applications.

The Effect of WC Doping on the Electrochemical Behavior of Nanosilicon/CMC/AB Composite Electrode

2011 ◽  
Vol 328-330 ◽  
pp. 1585-1588
Author(s):  
Zhong Sheng Wen ◽  
Dong Lu ◽  
Jun Cai Sun ◽  
Shi Jun Ji
Keyword(s):  
Mechanical Properties ◽  
Electrochemical Behavior ◽  
Composite Electrode ◽  
Lithium Ion ◽  
Composite Electrodes ◽  
X Ray Diffraction ◽  
Capacity Retention ◽  
Lithium Ions ◽  
Host Materials

Silicon is the most attractive anode material of all known host materials for lithium ion batteries because of its high theoretical lithium-insertion capacity up to 4200 mAh g-1, but it is difficult to be applied for its poor cyclability caused by the mechanical invalidation for the insertion of lithium ions. Nanosilicon/CMC/AB composite electrodes doped with WC were prepared by ball milling. The effect of the structure transformation of the doped electrode on the electrochemical behavior was systematically analyzed by X-ray diffraction. The mechanical properties of doped silicon electrode play an important role on its long-term electrochemical stability. The capacity retention could be maintained about 90% after 40 cycles. It was demonstrated that the cycling stability of the nanosilicon composite electrode could get a great promotion by WC doping. The intensification of the mechanical properties is critical to enhance the performance of the composite electrode.

Numerical Investigation on Diffusion-Induced Cracking in Solid Electrolyte of Composite Electrode and Its Impact on the Li-Ion Conductivity

2021 ◽  
Author(s):  
Ying HUANG ◽  
Fangzhou ZHANG ◽  
Qiu-An HUANG ◽  
Yaolong HE ◽  
Jiujun Zhang
Keyword(s):  
Solid Electrolyte ◽  
Active Material ◽  
Lithium Ion ◽  
Homogenization Method ◽  
Ion Conductivity ◽  
Composite Electrodes ◽  
Fem Model ◽  
Dimensional Finite Element ◽  
Stable Performance ◽  
Li Ion

Abstract In this paper, the cracking of the solid electrolyte (SE) and its impacts on the effective Li-ion conductivity of composite electrodes of all-solid-state lithium-ion batteries (ASSLIBs) are investigated numerically. A two-dimensional finite element (2D FEM) model was developed for composite electrodes in which active material particles (AM particles) are embedded in the solid electrolyte. The 2D FEM model can successfully calculate and simulate the diffusion-induced stress, the generation of solid electrolyte cracks (SE cracks), and the Li-ion transport. The degradation of Li-ion conductivity for cracked composite electrodes is calculated with the homogenization method. It is revealed that the diffusion-induced volume variation in AM particles can generate significant stress and thus SE cracking in composite electrodes of ASSLIBs. The calculated results suggest that swelling AM particles are more favorable than shrinking AM particles for the structural stability of composite electrodes. It is also demonstrated that the evolution of the conductivity with the propagation of SE cracking is consistent with the percolation theory. The fundamental understating of the SE cracking and its impact in this paper may benefit the design of novel ASSLIBs with more stable performance and a longer lifespan.

scholarly journals Nanocrystalline iron oxide based electroactive materials in lithium ion batteries: the critical role of crystallite size, morphology, and electrode heterostructure on battery relevant electrochemistry

2016 ◽  
Vol 3 (1) ◽  
pp. 26-40 ◽  
Author(s):  
Andrea M. Bruck ◽  
Christina A. Cama ◽  
Cara N. Gannett ◽  
Amy C. Marschilok ◽  
Esther S. Takeuchi ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Lithium Ion Batteries ◽  
Crystallite Size ◽  
Critical Role ◽  
Lithium Ion ◽  
Composite Electrodes ◽  
Electroactive Materials ◽  
Nanocrystalline Iron

The whole versus the sum of its parts; contributions of nanoscale iron-containing materials to the bulk electrochemistry of composite electrodes.

scholarly journals The Effect of Silicon Grade and Electrode Architecture on the Performance of Advanced Anodes for Next Generation Lithium-Ion Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3448
Author(s):  
Alexandra Meyer ◽  
Fabian Ball ◽  
Wilhelm Pfleging
Keyword(s):  
Electrochemical Impedance ◽  
Active Material ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Composite Electrodes ◽  
Counter Electrodes ◽  
Transfer Resistance ◽  
Graphite Composite ◽  
Lithium Ion Cells

To increase the specific capacity of anodes for lithium-ion cells, advanced active materials, such as silicon, can be utilized. Silicon has an order of magnitude higher specific capacity compared to the state-of-the-art anode material graphite; therefore, it is a promising candidate to achieve this target. In this study, different types of silicon nanopowders were introduced as active material for the manufacturing of composite silicon/graphite electrodes. The materials were selected from different suppliers providing different grades of purity and different grain sizes. The slurry preparation, including binder, additives, and active material, was established using a ball milling device and coating was performed via tape casting on a thin copper current collector foil. Composite electrodes with an areal capacity of approximately 1.70 mAh/cm² were deposited. Reference electrodes without silicon were prepared in the same manner, and they showed slightly lower areal capacities. High repetition rate, ultrafast laser ablation was applied to these high-power electrodes in order to introduce line structures with a periodicity of 200 µm. The electrochemical performance of the anodes was evaluated as rate capability and operational lifetime measurements including pouch cells with NMC 622 as counter electrodes. For the silicon/graphite composite electrodes with the best performance, up to 200 full cycles at a C-rate of 1C were achieved until end of life was reached at 80% relative capacity. Additionally, electrochemical impedance spectroscopies were conducted as a function of state of health to correlate the used silicon grade with solid electrolyte interface (SEI) formation and charge transfer resistance values.

scholarly journals The Influence of Structure on the Electrochemical and Thermal Response of Li-Ion Battery Electrodes

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Prehit Patel ◽  
George J. Nelson
Keyword(s):  
Particle Size ◽  
Heat Generation ◽  
Active Material ◽  
Thermal Response ◽  
Lithium Ion ◽  
Local Heat ◽  
Spherical Particles ◽  
Electrode Thickness ◽  
Material Particle ◽  
Fast Charging

Abstract Advancement of lithium-ion batteries for transportation applications requires addressing two key challenges: increasing energy density and providing fast charging capabilities. The first of these challenges can be met using thicker electrodes. However, the implementation of thick electrodes inherently presents a trade-off with respect to fast charging. As the thickness is increased, transport limitations reduce the ability of the battery to meet aggressive charge conditions. At the particle scale, interactions between solid diffusion and reaction kinetics influence the effective storage of lithium. At the electrode scale, diffusion limitations can lead to local variations in salt concentrations and electric potential. These short-range and long-range effects can combine to influence local current and heat generation. In the present work, a pseudo-2D lithium-ion battery model is applied to understand how active material particle size, porosity, and electrode thickness impact local field variables, current, heat generation, and cell capacity within a single-cell stack. The model was built assuming that the active particles are representative spherical particles. The governing equations and boundary conditions were set following the common Newman model. Cell response under varied combinations of charge and discharge cycling is assessed for rates of 1 C and 5 C. Aggressive charge and discharge conditions lead to locally elevated C-rates and attendant increases in local heat generation. These variations can be impacted in part by tailoring electrode structures. To this end, results for parametric studies of active material particle size, porosity, and electrode thickness are presented and discussed.

The Influence of Structure on the Electrochemical and Thermal Response of Li-Ion Battery Electrodes

2019 ◽  
Author(s):  
Prehit Patel ◽  
George J. Nelson
Keyword(s):  
Particle Size ◽  
Lithium Ion Battery ◽  
Heat Generation ◽  
Active Material ◽  
Lithium Ion ◽  
Spherical Particles ◽  
Electrode Thickness ◽  
Material Particle ◽  
Trade Off ◽  
Fast Charging

Abstract The continued advancement of lithium ion batteries for transportation applications requires addressing two key challenges: increasing energy density and providing fast charging capabilities. The first of these challenges can be met in part through the use of thicker electrodes, which reduce the electrochemically inactive mass of the cell. However, implementation of thick electrodes inherently presents a trade-off with respect to fast charging capabilities. As thickness is increased, transport limitations exert greater influence on battery performance and reduce the ability of the battery to meet aggressive charge conditions. This trade-off can manifest over multiple length scales. At the particle-scale, interactions between solid diffusion and reaction kinetics influence the effective storage of lithium within the active material. At the electrode scale, diffusion limitations can lead to local variations in salt concentrations and electric potential. These short-range and long-range effects can combine to influence local current and heat generation. In the present work, a pseudo-2D lithium ion battery model is applied to understand how active material particle size, porosity, and electrode thickness impact local field variables, current, heat generation, and cell capacity within a single cell stack. COMSOL Multiphysics 5.2 is used to implement the pseudo-2D model of a lithium ion battery consisting of a graphite negative electrode, polymer separator, and lithium transition metal oxide positive electrode. Lithium hexafluorophosphate (LiPF6) in 1:1 ethylene carbonate (EC) and diethylene carbonate (DEC) was used as the electrolyte. The model was built assuming that the active particles are representative spherical particles. The governing equations and boundary conditions were set following the common Newman model. Cell response under varied combinations of charge and discharge cycling is assessed for rates of 1C and 5C. Aggressive charge and discharge conditions lead to locally elevated C-rates and attendant increases in local heat generation. These variations can be impacted in part by tailoring electrode structures. To this end, results for parametric studies of active material particle size, porosity, and electrode thickness are presented and discussed.

Sign in / Sign up

Export Citation Format

Share Document