Effects of Styrene-Butadiene Rubber/Carboxymethylcellulose (SBR/CMC) and Polyvinylidene Difluoride (PVDF) Binders on Low Temperature Lithium Ion Batteries

Abstract

Effects of styrene-butadiene rubber/carboxymethylcellulose (SBR/CMC) and polyvinylidene difluoride (PVDF) binders on the electrochemical characteristics of a type of microsize MCMB (mesocarbon microbeads) anode (SMA) at low temperature are investigated by cold/heat shock testing, differential scanning calorimetry, scanning electron microscopy, electrochemical impedance spectroscopy, coin cell testing and 18650 full cell testing. Under low temperature conditions and compared to the SMA electrode with a SBR/CMC binder, the SMA electrode with a PVDF binder has lower impedance, lower charge transfer resistance, better rate capability and superior cycleability.Lithium ion batteries (LIBs) are at present dominating as power supplies in small sized general portable consumer electronics applications in the information technology (IT) industry. During recent decades, LIBs have undergone revolutionary technological progress in design and application. Development of LIBs for low temperature use has become an issue of great concern, especially for high power applications such as in aerospace, military and hybrid electric vehicles. 1-3 Lithium insertion and extraction in anode materials involve solid/electrolyte interface (SEI) formation, 4,5 although the twophase reaction theory has been challenged at low temperatures. In any case, it is widely observed that the insertion and extraction of lithium is more difficult at low temperatures. Great efforts have been made to enhance the lithium ion transport properties of SEI films on carbon anodes by approaching cell design from the related low temperature conditions. 6-8 Most previous researchers 9-13 have attempted to improve LIB low temperature performance by developing electrolytes with increased ionic conductivities. Among such studies, application of micro-sized materials and their shorter ionic diffusion paths to electrodes is considered one of the attractive solutions to the problem. However, recent work 14,15 has demonstrated that the primary cause of poor Li-ion cell performance at low temperatures is not related to organic electrolytes or SEI films but is in fact related to Li ion diffusion in negative electrodes with a polyvinylidene difluoride (PVDF) binder. The resistance to ionic flow at low temperatures is therefore a major factor in the performance of carbon-based negative electrodes in LIBs.Most polymers at room temperature show the familiar polymeric properties of material flexibility and high resistance to cracking. Typically, the long molecular chains of most polymers at moderate temperatures are able to stretch, deform and slither over one another. Accordingly, at normal temperatures, polymer materials are flexible, do not crack and are considered to be in a 'rubbery' state. But when the temperature drops through the 'glass transition region,' i.e. falls below the glass transition temperature (Tg), most polymers stiffen up and become glassy solids that are very hard and brittle. For the −40 • C to 80 • C operating temperature range of Li-ion batteries, low tem...

Highly Stretchable Conductive Glue for High‐Performance Silicon Anodes in Advanced Lithium‐Ion Batteries

“…[3b,4] A huge volume change over 300% in Si during lithiation and delithiation undermines the electrode integrity as illustrated in Figure a, resulting in quick capacity fading. To improve the mechanical stability of Si anodes, functional binders such as polyamide imide, poly(acrylic acid) (PAA), polyimide, carboxymethyl cellulose (CMC), alginate, cyclodextrin, CMC/styrene‐butadiene rubber, and PAA/poly(vinyl alcohol) have been developed. These binders exhibit improved adhesion and binding on Si nanoparticles (SiNPs) by forming hydrogen bonds and/or covalent chemical bonds with surface SiO 2 layer of SiNPs, thereby resulting in improved cycle lifetime.…”

Water‐Soluble Acrylate Binder for Graphite Electrodes in Lithium‐Ion Batteries

“…When the C-rate is further increased to 1C at 0 8C, the capacity of the Acryl S020 electrode drops to 25 mAh g À1 and that of the CMC + SBR electrode close to zero.I th as previously been reported that graphite electrodes with CMC + SBR binders show lower performance than PVDF-basedg raphite electrodes at low temperatures in terms of rate capability and stability. [9] This was explained by structural changes of the CMC + SBR electrodes induced by the low temperature.…”

Organic Solvent Free Process to Fabricate High Performance Silicon and Graphite Composite Anode

“…Conventionally, poly (vinylidene difluoride) (PVDF) binder is widely used for Li-ion cells due to its good electrochemical stability and binding capability. However, the process using PVDF normally requires the usage of organic solvents like N-methyl-2-pyrrolidone (NMP), which is potentially hazardous and not cost efficient [15,16] . Therefore, it will be beneficial to develop binders that can be processed with less toxic, or even non-toxic solvents.…”

“…Therefore, it will be beneficial to develop binders that can be processed with less toxic, or even non-toxic solvents. Recently, it was reported that water-based binder such as styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) effectively improves the cycling stability of silicon electrode [15][16][17][18][19][20][21][22][23][24][25][26] . According to a previous report by Hochgatterer et al [21] , the formation of a covalent chemical bond between the CMC and silicon particle plays an important role in the effective binding and improved performance.…”