Consumer electronics users are increasingly choosing smart phones that provide a web-connected experience together with a high degree of portability. User activities such as web surfing and
gaming consume significant amounts of stored energy, far greater than that of simple mobile phones. Additionally, the portability of these devices requires a small size and weight compared
with traditional laptop computers. This combination of increased energy consumption from smaller and lighter weight devices presents a significant challenge for the lithium batteries
that provide the onboard energy storage. Cell volumetric and gravimetric energy density targets for advanced devices cannot be met with traditional carbon anodes due to the materials
inherent low capacity. A new class of “beyond graphite” anodes are required. Silicon, a promising graphite replacement due to its capacity (4,200 mAh/g) and lithiation voltage
range (0.0 ~ 0.4 V) but poor cycle life and excessive volumetric expansion have slowed commercial adoption. A high-performance & low-cost Si-based anode remains a crucial need of
the battery industry.
XG Sciences (XGS) is launching a new generation of its SiG silicon-graphene anode material. The new generation of material delivers substantial improvements in cycle life and volumetric
expansion compared to the first generation material. The new anode incorporates several changes to the material physical properties and manufacturing process that are responsible
for the performance improvements. Tap density of 0.88 g/cc and reduced surface area continue to provide good processability. The new material is produced in the existing ton-scale
manufacturing plant ensuring availability in volumes necessary for commercial cell programs. Typical full cell cycling performance (Silicon anode/ NCA cathode) is shown in Figure
1. SiG electrodes compressed to 1.6 g/cc have demonstrated swelling of less than 35 percent.Figure 1 New XGS Silicon-based anode material cycled in full cell (C/2) between 3 - 4.2 V.
In addition, the new material has shown comparable cycling capacity stability over wide voltage ranges which normally present significant challenges for silicon-based anodes. The wide
operating voltage range enables cell manufactures to maximize energy density for their high energy products.
Dispersion of the new SiG anode material has also been improved and demonstrated using typical industrial double planetary mixers. SiG anode slurry formulated with aqueous CMC/SBR binder
and has been successfully coated using pilot scale commercial coaters. Coating quality has been confirmed through inspection of electrodes compressed to 1.8 g/cc. This presentation
will include details of the new SiG nanocomposite anode material, dispersion and mixing developments using industrial scale equipment and full cell cycling performance information.
The stable cycling performance of the new SiG silicon-graphene anode material confirms the effectiveness of XGS’ anode material design strategy utilizing graphene nanoplatelets
in mitigating the detrimental effects of Silicon particle expansion and contraction and improving the cycle life of the Silicon anode.
XG Sciences acknowledges the U.S. Department of Energy SBIR program that provided support for this work.