Poly(vinylidene fluoride) separators for next‐generation lithium based batteries

Abstract

Lithium-ion batteries (LIBs) have become star products in wireless electronic equipment, new energy vehicles and many other fields due to their advantages of high energy density, light weight, good stability, high charging-discharging efficiency, long service life and environmental friendliness. The separator is an indispensable part of batteries that does not participate in electrochemical reactions, separating the anode and cathode. It has a microporous structure, which can store electrolyte and allow ions to transfer freely. Poly(vinylidene fluoride) (PVDF)-based separators are characterized by strong polarity, high dielectric constant, stable electrochemical performance, excellent tensile properties and mechanical strength, favorable thermal stability and wettability. Therefore, they are proposed to be potential candidates for novel separators in the field of LIBs. This review introduces the recent researches and advances in PVDF-based separators for LIBs, with the characterizations and requirements for separators. It is mainly divided into the two types including monolayer and multilayer separators. Furthermore, the performance of the PVDF-based separators is summarized, and the challenges and prospects in their practical application are briefly analyzed.

Comparison of lithium‐ion battery cell technologies applied in the regenerative braking system

“…The specifications of the four cells are shown in Table 1. The focus of this research is on performance comparison of the above cell technologies using electrical testing, checking the suitability of the prototype cell, and finding the best technology for pack development for RBS application; however, the in‐detailed manufacturing details of the porotype cell can be found in Liu et al 61 …”

Electrospun polar-nanofiber PVDF separator for lithium–sulfur batteries with enhanced charge storage capacity and cycling durability

“…33 Many methods have been developed to prepare b-phase PVDF, such as solvent casting, electrospinning, annealing, polymer stretching, and incorporation of filler materials. Electrospinning of PVDF nanofibers has become one of the most promising techniques 30,34 and can provide membranes with high porosity, high specific surface area and controllable pore size, and can improve the wettability for electrolytes. In the electrospinning method, a PVDF solution in organic solvent is prepared and loaded into a spinneret with a hollow needle, which is then placed under a high electric field (B10 6 V m À1 ).…”

“…29 This area has been extensively reviewed by He and co-workers. 30 Continuous porous membranes and nanofibrous PVDF-containing materials produced by standard syringe techniques ( e.g. ref.…”

Advanced Sustainable Trilayer Cellulosic “Paper Separator” Functionalized with Nano-BaTiO3 for Applications in Li-Ion Batteries and Supercapacitors

“…Conventionally used microporous polyolefin (polypropylene/polyethylene)-based plastic separators have no doubt been a great commercial success in Li-ion batteries till date, but their low wettability towards commercial electrolytes, dimensional instability at elevated temperature, and environmental challenges due to plastic toxicity trigger the need for more advanced sustainable separators for lithium-ion batteries (LIBs) . To mitigate these problems, two major approaches were undertaken: either surface modification of existing polyethylene (PE)/polypropylene (PP)-based separators or employment of other synthetic polymers, which include poly­(ethylene terephthalate) (PET) nonwovens, polyacrylonitrile (PAN), poly­(vinylidene fluoride) (PVDF), etc …”

“…3 To mitigate these problems, two major approaches were undertaken: either surface modification of existing polyethylene (PE)/polypropylene (PP)-based separators 4 or employment of other synthetic polymers, which include poly(ethylene terephthalate) (PET) nonwovens, 5 polyacrylonitrile (PAN), 6 poly(vinylidene fluoride) (PVDF), etc. 7 Besides these synthetic polymers, cellulose and/or its derivatives, e.g., bacterial cellulose, 8,9 cellulose acetates, 10 carboxymethyl cellulose, 11 cellulose nanofibers or nanocrystals, 12,13 lignocellulose 14 etc., have also been investigated widely as separator membranes. The obvious reasons for choosing cellulose as the separator material is definitely due to its sustainability, natural abundance, lower cost, and ease to compositionally modify or functionalize to achieve the desired properties as separator membranes in batteries.…”