Recent advances on separator membranes for lithium-ion battery applications: From porous membranes to solid electrolytes

Recycling and environmental issues of lithium-ion batteries: Advances, challenges and opportunities

Lithium-ion batteries (LIBs) are promising energy storage devices for integrating renewable resources and high power applications, owing to their high energy density, light weight, high flexibility, slow self-discharge rate, high rate charging capability, and long battery life. LIBs work efficiently at ambient temperatures, however, at high-temperatures, they cause serious issues due to the thermal fluctuation inside batteries during operation. The separator is a key component of batteries and is crucial for the sustainability of LIBs at high-temperatures. The high thermal stability with minimum thermal shrinkage and robust mechanical strength are the prime requirements along with high porosity, ionic conductivity, and electrolyte uptake for highly efficient high-temperature LIBs. This Review deals with the recent studies and developments in separator technologies for high-temperature LIBs with respect to their structural layered formation. The recent progress in monolayer and multilayer separators along with the developed preparation methodologies is discussed in detail. Future challenges and directions toward the advancement in separator technology are also discussed for achieving remarkable performance of separators in a high-temperature environment.

Recent Development in Separators for High-Temperature Lithium-Ion Batteries

Polyvinylidene fluoride (PVDF) is among the most attractive piezo-polymers due to its excellent piezoelectricity, lightweight, flexibility, high thermal stability, and chemical resistance. PVDF can exist under different forms of films, membranes, and (nano)fibers, and its piezoelectric property related to its β phase content makes it interesting for energy harvesters and wearable applications. Research investigation shows that PVDF in the form of nanofibers prepared by electrospinning has more flexibility and better air permeability, which make them more suitable for these types of applications. Electrospinning is an efficient technique that produces PVDF nanofibers with a high β phase fraction and crystallinity by aligning molecular dipoles (–CH2 and –CF2) along an applied voltage direction. Different nanofibers production techniques and more precisely the electrospinning method for producing PVDF nanofibers with optimal electrospinning parameters are the key focuses of this paper. This review article highlights recent studies to summarize the influence of electrospinning parameters such as process (voltage, distance, flow rate, and collector), solution (Mw, concentration, and solvent), and ambient (humidity and temperature) parameters to enhance the piezoelectric properties of PVDF nanofibers. In addition, recent development regarding the effect of adding nanoparticles in the structure of nanofibers on the improvement of the β phase is reviewed. Finally, different methods of measuring piezoelectric properties of PVDF nanofibrous membrane are discussed.

https://www.mdpi.com/2073-4360/13/2/174/pdf

Electrospun PVDF Nanofibers for Piezoelectric Applications: A Review of the Influence of Electrospinning Parameters on the β Phase and Crystallinity Enhancement.

A novel blended solid polymer electrolyte comprising polyethylene oxide and polyvinylpyrrolidone polymers for blending and sodium nitrate (NaNO3) as ion conducting species has been optimized via standard solution-cast technique. XRD, FESEM, and FTIR were performed to obtain the information about the structural changes, morphology, and microstructural changes (polymer–ion and ion–ion interactions) of the solid polymer electrolyte films. The electrochemical impedance spectroscopy, linear sweep voltammetry, and i–t characteristics were performed to evaluate the ionic conductivity, voltage stability window, and ion transference number. The impedance study was done in a broad temperature range (40–100 °C). The DSC and TGA were used to obtain information about the thermal transitions and thermal stability of prepared films. The ion dynamics is further investigated by analyzing the complex permittivity, loss tangent, and complex conductivity. All the plots were fitted through established theoretical model/expressions in whole frequency window to obtain dielectric strength, ion conduction path behavior, and relaxation time. Transport parameters such as number density (n), mobility (μ), and diffusion coefficient (D) of mobile ions were obtained by three methods and compared satisfactorily. Lastly, a coherent mechanism for the migration of charge transport carriers within the solid polymer composites has been proposed based on the performed experimental outcome.

Dielectric relaxations and transport properties parameter analysis of novel blended solid polymer electrolyte for sodium-ion rechargeable batteries

The separator membrane is an essential component of lithium-ion batteries, separating the anode and cathode, and controlling the number and mobility of the lithium ions. Among the polymer matrices most commonly investigated for battery separators are poly(vinylidene fluoride) (PVDF) and its copolymers poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and poly(vinylidene fluoride-cochlorotrifluoroethylene) (PVDF-CTFE), due to their excellent properties such as high polarity and the possibility of controlling the porosity of the materials through binary and ternary polymer/solvent systems, among others. This review presents the recent advances on battery separators based on PVDF and its copolymers for lithium-ion batteries. It is divided into the following sections: single polymer and co-polymers, surface modification, composites, and polymer blends. Further, a critical comparison between those membranes and other separator membranes is presented, as well as the future trends on this area.

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Recent Advances in Poly(vinylidene fluoride) and Its Copolymers for Lithium-Ion Battery Separators

Data science has started to become one of the most important skills one can have in the modern world, due to data taking an increasingly meaningful role in our lives. The accessibility of data science is however limited, requiring complicated software or programming knowledge. Both can be challenging and hard to master, even for the simple tasks.

/pdf/data-curation-towards-a-tool-for-all-4hv40ctqp8.pdf

José P. Dias

Papers

Recent Advances in Poly(vinylidene fluoride) and Its Copolymers for Lithium-Ion Battery Separators

Data Curation: Towards a Tool for All