Improved composite electrode and lithium battery performance From smart use of the polymers and their properties

ABSTRACTTo increase electrode cycling performance in batteries, most researchers generally focus their work on the active material optimisation. Here we show that the polymeric binder of the composite electrode may have an important role on the electrode performance. We describe a new tailored polymeric binder combination with controlled polymer-filler (carbon black) interactions that allows the preparation of new and more efficient electrode architecture. Using this polymeric binder, composite electrodes based on Li1.2V3O8 display a room-temperature cycling capacity of 280 mAh/g (C/5 rate, 3.3–2 V) instead of 150 mAh/g using a standard-type (PVdF-HFP binder) composite electrode. We have coupled SEM observations, galvanostatic cycling and electronic conductivity measurements in order to define and understand the impact of the microstructure of the composite electrode on its electrochemical performance.

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The Effect of Active Material, Conductive Additives, and Binder in a Cathode Composite Electrode on Battery Performance

Energies ◽

10.3390/en12040658 ◽

2019 ◽

Vol 12 (4) ◽

pp. 658 ◽

Cited By ~ 11

Author(s):

Yoon Lee

Keyword(s):

Composite Electrode ◽

Electronic Conductivity ◽

Active Material ◽

Transition Metal Ions ◽

Polymer Binder ◽

Cell Performance ◽

Side Reactions ◽

Interfacial Resistance ◽

Battery Capacity ◽

Conductive Additives

The current study investigated the effects of active material, conductive additives, and binder in a composite electrode on battery performance. In addition, the parameters related to cell performance as well as side reactions were integrated in an electrochemical model. In order to predict the cell performance, key parameters including manganese dissolution, electronic conductivity, and resistance were first measured through experiments. Experimental results determined that a higher ratio of polymer binder to conductive additives increased the interfacial resistance, and a higher ratio of conductive additives to polymer binder in the electrode resulted in an increase in dissolved transition metal ions from the LiMn2O4 composite electrode. By performing a degradation simulation with these parameters, battery capacity was predicted with various fractions of constituents in the composite electrode. The present study shows that by using this integrated prediction method, the optimal ratio of constituents for a particular cathode composite electrode can be specified that will maximize battery performance.

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

Polymers ◽

10.3390/polym12071460 ◽

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.

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Double-Layer Solid Composite Electrolytes Enabling Improved Room-Temperature Cycling Performance for High-Voltage Lithium Metal Batteries

ACS Omega ◽

10.1021/acsomega.1c05576 ◽

2021 ◽

Author(s):

Lei Zou ◽

Kun Shi ◽

Zhengjie Xu ◽

Zeheng Yang ◽

Weixin Zhang

Keyword(s):

Double Layer ◽

High Voltage ◽

Room Temperature ◽

Cycling Performance ◽

Temperature Cycling ◽

Lithium Metal ◽

Composite Electrolytes ◽

Lithium Metal Batteries

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Impact of Graphite Materials on the Lifetime of NMC811/Graphite Pouch Cells: Part I. Material Properties, ARC Safety Tests, Gas Generation, and Room Temperature Cycling

Journal of The Electrochemical Society ◽

10.1149/1945-7111/ac39fc ◽

2021 ◽

Author(s):

Ahmed Eldesoky ◽

Michael Bauer ◽

Saad Azam ◽

Eniko zsoldos ◽

Wentao Song ◽

...

Keyword(s):

Room Temperature ◽

Temperature Cycling ◽

Cell Swelling ◽

Bet Surface Area ◽

Gas Generation ◽

Capacity Retention ◽

Surface Areas ◽

Li Ion ◽

Accessible Surface ◽

The Impact

Abstract The impact of graphite materials on capacity retention in Li-ion cells is important to understand since Li inventory loss due to SEI formation, and cross-talk reactions between the positive and negative electrodes, are important cell failure mechanisms in Li-ion cells. Here, we investigate the impact of five graphite materials from reputable suppliers on the performance of NMC811/graphite cells. We show that natural graphites (NG) here have a mixture of 3R and 2H phases, while artificial graphites (AG) were 2H only. We find that there are differences between the N2 BET surface area and the electrochemically-accessible area where redox reactions can take place and it is the latter that is most important when optimizing graphite-containing cells. Part I of this 2-part series investigates physical and electrochemical differences between the graphite materials of interest here, as well as room temperature cycling to probe improvements in capacity retention. We demonstrate that advanced AG materials with small accessible surface areas can improve safety, 1st cycle efficiency (FCE) and long-term cycling. Part II of this work examines elevated temperature cycling, cell swelling, and makes lifetime predictions for the best NMC811/graphite cells.

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Heat-Treated Fe3O4 - Activated Carbon Nanocomposite for High Performance Electrochemical Capacitor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.894.349 ◽

2014 ◽

Vol 894 ◽

pp. 349-354 ◽

Cited By ~ 1

Author(s):

M.Y. Ho ◽

Poi Sim Khiew

Keyword(s):

Activated Carbon ◽

High Performance ◽

Electrochemical Impedance ◽

Diffusion Mechanism ◽

Electronic Conductivity ◽

Treatment Temperature ◽

Constant Current ◽

Composite Electrodes ◽

The Impact ◽

Carbon Nanocomposite

The impact of heat treatment temperature on the electrochemical performance of Fe3O4-activated carbon nanocomposite electrodes was investigated using constant current charge-discharge and Electrochemical Impedance Spectroscopy (EIS). An improved capacitive behaviour was observed due to the effect of enhanced ionic and electronic conductivities of the 4 wt% Fe3O4/AC by thermally heating at 200 °C for 6 hours. It was found that the internal resistance of 4 wt% Fe3O4/AC composite electrode calcined at 200 °C for 6 hours is the smallest (2.97 Ω) in comparison to those untreated (4.36 Ω) composite electrodes. The ion mobility inside the porous composite electrodes is favourable at 200 °C, accompanying with the enhanced electronic conductivity of oxide electrode as a result of improved crystallinity. The EIS results and analysis not only have significant impact on the fundamental understanding of the temperature-dependent structural and electrochemical properties of electrode but also provide the insights on the diffusion mechanism of the nanocomposite in neutral Na2SO3electrolyte.

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A hybrid dual-salt polymer electrolyte for sodium metal batteries with stable room temperature cycling performance

Energy Storage Materials ◽

10.1016/j.ensm.2022.01.001 ◽

2022 ◽

Author(s):

Ho Mei Law ◽

Jing Yu ◽

Stephen C.T. Kwok ◽

Guodong Zhou ◽

Matthew J. Robson ◽

...

Keyword(s):

Polymer Electrolyte ◽

Room Temperature ◽

Cycling Performance ◽

Temperature Cycling ◽

Sodium Metal

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Polyaniline Nanotubes/Carbon Cloth Composite Electrode by Thermal Acid Doping for High-Performance Supercapacitors

Polymers ◽

10.3390/polym11122053 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2053 ◽

Cited By ~ 1

Author(s):

Jia Hui ◽

Daoxin Wei ◽

Jing Chen ◽

Zhou Yang

Keyword(s):

High Performance ◽

Room Temperature ◽

Composite Electrode ◽

Low Cost ◽

Electrochemical Performances ◽

Carbon Cloth ◽

Composite Electrodes ◽

Energy Storage Devices ◽

Storage Devices ◽

One Step

Carbon materials have been widely used in designing supercapacitors (SCs) but the capacitance is not ideal. Herein, we synthesize polyaniline (PANI) nanotubes on the basis of a carbon cloth (CC) through a one-step self-degradation template method, and fabricate a CC@PANI NTs-H (CC@PANI nanotubes doping at high temperature) composite electrode by thermal acid doping. The CC@PANI NTs-H electrode obviously exhibits better electrochemical performance with a gravimetric capacitance of 438 F g−1 and maintains 86.8% after 10,000 cycles than the CC@PANI NTs-R (CC@PANI nanotubes doping at room temperature) electrode. Furthermore, we assemble a flexible solid state supercapacitor (FSSC) device with the as-prepared CC@PANI NTs-H composite electrodes, showing good flexibility and outstanding electrochemical performances with a high gravimetric capacitance of 247 F g−1, a large energy density of 21.9 Wh kg−1, and a capacitance retention of 85.4% after 10,000 charge and discharge cycles. Our work proposes a novel and easy pathway to fabricate low-cost FSSCs for the development of energy storage devices.

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Electrochemical Performance of Thick-Film Li(Ni0.6Mn0.2Co0.2)O2 Cathode with Hierarchic Structures and Laser Ablation

Nanomaterials ◽

10.3390/nano11112962 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2962

Author(s):

Zelai Song ◽

Penghui Zhu ◽

Wilhelm Pfleging ◽

Jiyu Sun

Keyword(s):

Thin Film ◽

Particle Size ◽

Laser Ablation ◽

Electrochemical Performance ◽

Thick Film ◽

Active Material ◽

Lithium Ion ◽

Particle Morphology ◽

Composite Electrodes ◽

The Impact

The electrochemical performance of lithium-ion batteries is directly influenced by type of active material as well as its morphology. In order to evaluate the impact of particle morphology in thick-film electrodes, Li(Ni0.6Mn0.2Co0.2)O2 (NMC 622) cathodes with bilayer structure consisting of two different particle sizes were manufactured and electrochemically characterized in coin cells design. The hierarchical thick-film electrodes were generated by multiple casting using NMC 622 (TA) with small particle size of 6.7 µm and NMC 622 (BA) with large particle size of 12.8 µm. Besides, reference electrodes with one type of active material as well as with two type of materials established during mixing process (BT) were manufactured. The total film thickness of all hierarchical composite electrodes were kept constant at 150 µm, while the thicknesses of TA and BA were set at 1:2, 1:1, and 2:1. Meanwhile, three kinds of thin-film cathodes with 70 µm were applied to represent the state-of-the-art approach. Subsequently, ultrafast laser ablation was applied to generate groove structures inside the electrodes. The results demonstrate that cells with thin-film or thick-film cathode only containing TA, cells with bilayer electrode containing TBA 1:2, and cells with laser-structured electrodes show higher capacity at C/2 to 5C, respectively.

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