By adding graphene bundles, scientists have successfully solved the inherent performance problems of silicon, the second most abundant element in the Earth's crust, which weighs 10 times more than graphite. This has increased the battery's capacity and more than doubled its lifespan.
In lithium-ion batteries, silicon, with its extremely high specific capacity, suffers from capacity decay. Due to its volume expansion during lithiation, silicon particles can chemically aggregate together, forming an insulating interface layer. Since silicon inherently lacks sufficient elasticity to cope with lithiation strain during repeated charging, this can lead to the cracking, pulverization, and rapid physical degradation of the anode composite microstructure.
However, researchers at the University of Warwick in the UK have discovered a new type of anode mixture that can be manufactured on an industrial scale. By separating several connected graphene layers, researchers were able to obtain several layers of graphene (FLG) material.
According to a research report titled "Related Impedance Study of Silicon-Few-Quantity Graphene (FLG) Composite Electrode System" published in Natural Science Reports, FLG materials can significantly improve the performance of larger-sized silicon particles used as anodes.
Therefore, the researchers created a hybrid anode consisting of 60% microsilica particles, 16% FLG, 14% sodium/polyacrylic acid, and 10% carbon additives, and then performed 100 charge-discharge cycles to examine its performance and changes in the material structure.
The FLG flakes enhance the material's elasticity and tensile properties, significantly reducing the damage caused by the physical expansion of lithium during silaneization. Dr. Melanie Loveridge, a senior researcher at the School of Engineering at the University of Warwick and the lead researcher, said, "More importantly, these FLG flakes can also very effectively maintain the degree of separation between silicon particles."
The research team has begun working with the University of Cambridge, CIC, Lithops, and IIT (Italian Polytechnic Institute) to further investigate this two-year project led by Varta Micro-innovations, to produce silicon/graphene composites for use in high-energy and high-power lithium-ion batteries.
