Battery Separators

Abstract

The ideal battery separator would be infinitesimally thin, offer no resistance to ionic transport in electrolytes, provide infinite resistance to electronic conductivity for isolation of electrodes, be highly tortuous to prevent dendritic growths, and be inert to chemical reactions. Unfortunately, in the real world the ideal case does not exist. Real world separators are electronically insulating membranes whose ionic resistivity is brought to the desired range by manipulating the membranes thickness and porosity. It is clear that no single separator satisfies all the needs of battery designers, and compromises have to be made. It is ultimately the application that decides which separator is most suitable. We hope that this paper will be a useful tool and will help the battery manufacturers in selecting the most appropriate separators for their batteries and respective applications. The information provided is purely technical and does not include other very important parameters, such as cost of production, availability, and long-term stability. There has been a continued demand for thinner battery separators to increase battery power and capacity. This has been especially true for lithiumion batteries used in portable electronics. However, it is very important to ensure the continued safety of batteries, and this is where the role of the separator is greatest. Thus, it is essential to optimize all the components of battery to improve the performance while maintaining the safety of these cells. Separator manufacturers should work along with the battery manufacturers to create the next generation of batteries with increased reliability and performance, but always keeping safety in mind. This paper has attempted to present a comprehensive review of literature on separators used in various batteries. It is evident that a wide variety of separators are available and that they are critical components in batteries. In many cases, the separator is one of the major factors limiting the life and/or performance of batteries. Consequently, development of new improved separators would be very beneficial for the advanced high capacity batteries.

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

“…[ 44 ] They introduced a bifunctional electrocatalyst, Pt 0.5 Au 0.5 (PtAu) nanoparticles ( Figure 5 ). PtAu nanoparticles (6-7 nm diameter) were synthesized by reducing HAuCl 4 and H 2 PtCl 6 in oleylamine and then loaded onto Vulcan carbon to yield 40 wt% PtAu/C. Interestingly, the PtAu catalyst exhibited ORR (ca.…”

“…Reaction (1) proceeds until the solubility of the zincate ion, Zn(OH) 4 2 − (aq), reaches a saturation point in the hydroxide electrolyte. After exceeding this point, zincate ions are decomposed to ZnO, a white solid powder that acts as an insulater.…”

A Core@sheath Nanofibrous Separator for Lithium Ion Batteries Obtained by Coaxial Electrospinning

“…The serious shrinkage of PP separator was originated from the stretching action during the fabrication. [1] According to the DSC analysis shown in Figure S7(a) of Supporting Information, PP and PVDF-HFP melt at around 160 and 140 8C, respectively, whereas the PI possesses superior thermal stability over 300 8C. Although the sheath layer of PVDF-HFP would melt at 140 8C shown in Figure S7(b) of Supporting Information, the thermosetting PI of core component retained intact and provided a stable host for the melting PVDF-HFP when above 140 8C.…”

“…[1][2][3][4][5] To avoid internal short circuit failure, a robust separator should play a significant role in securing battery safety. Polyolefin microporous membranes such as polyethylene (PE) and poly(propylene) (PP) have been commercially available as major separators for lithium ion battery.…”

“…Polyolefin microporous membranes such as polyethylene (PE) and poly(propylene) (PP) have been commercially available as major separators for lithium ion battery. [1,2] However, these polyolefin-based separators suffer from poor wettability, poor thermal shrinkage and low transverse mechanical strength. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The poor wettability impairs the power capability and cycle life of the battery, and brings additional disadvantages in the manufacturing speed.…”