Solvent-Free Fabrication of Thick Electrodes in Thermoplastic Binders for High Energy Density Lithium-Ion Batteries

Abstract

The rapid development of electric vehicles has generated a recent demand for high energy density lithium-ion batteries (LIBs). One simple, effective way to enhance energy density of LIBs is to increase the thickness of electrodes. However, the conventional wet process used to fabricate thick electrodes involves the evaporation of large amounts of organic solvents, which causes an inhomogeneous distribution of conductive additives and binders. This weakens the mechanical and electrochemical network between active materials, resulting in poor electrochemical performance and structural degradation. Herein, we introduce a new strategy to produce homogeneous thick electrodes by using a dry, solvent-free process. Instead of using a conventional PVDF (polyvinylidene fluoride) binder, we employed a phenoxy resin as the binder in dry process for the first time. This thermoplastic binder exhibits better ductile properties than PVDF in the way that it generates a uniform network structure that connects the active materials during the hot press process. This enables the production electrochemically stable electrodes without using organic solvents, which record capacity retention rates of 73.5% over 50 cycles at a 40 mg/cm2 of thick electrodes. By contrast, thick electrodes produced with a PVDF binder via wet processing only have a capacity retention rate of 21.8% due to rapid structural degradation.

Polymeric Binder Design for Sustainable Lithium-Ion Battery Chemistry

“…Additionally, addressing the insufficient capacity of the graphite anode (~372 mA h g − 1 ) involves incorporating high-capacity Si, with the effectiveness of these improvements relying heavily on the performance of binder materials [ 11 , 12 ]. For thick cathodes, issues such as electrode cracking and flaking during the fabrication process, as well as insufficient ionic transfer rates and electrode stability during repetitive cycling, must be addressed by designing high-performance polymer binders [ 13 , 14 , 15 , 16 , 17 ]. In the case of composite anodes, the suppression of large volume expansion and the continuous formation of solid–electrolyte-interface (SEI) byproducts necessitates the introduction of functional polymer binders.…”

Solvent-Free Processed Cathode Slurry with Carbon Nanotube Conductors for Li-Ion Batteries

“…Recently, owing to the demand for energy storage systems, including electric car batteries, the requirement for the production of secondary batteries, particularly, Li-ion batteries (LiB) is significantly high [ 1 , 2 , 3 , 4 , 5 , 6 ]. In addition to the advancements in the search for alternatives for energy storage systems, research has been devoted to developing high-performance LiBs with better safety and lifetime [ 7 , 8 , 9 , 10 , 11 , 12 ].…”

Selective Electrophoretic Deposition of Silicon Nanoparticles onto PAN‐Based Carbon Fiber as a Prospective Anode for Structural Li‐Ion Batteries

“…To date, the conventional slurry casting method has been commonly used for this particular purpose [30] . However, this method tends to produce inhomogeneous coating, which tends to reduce the electrochemical performance [31] . Therefore, it is necessary to achieve a well‐coated active material onto carbon fiber in order to enhance the electrochemical properties of the battery [32,33] .…”

“…[30] However, this method tends to produce inhomogeneous coating, which tends to reduce the electrochemical performance. [31] Therefore, it is necessary to achieve a well-coated active material onto carbon fiber in order to enhance the electrochemical properties of the battery. [32,33] Several techniques are considered to perform good deposition processes, such as sputtering, [34] chemical vapor deposition, [35] atomic layer deposition, [35,36] pulsed laser deposition, [37] and electrophoretic deposition.…”