The need for electric energy storage systems are in increasing demand. Lithium-ion batteries represent the best option for many applications such as hybrid and electric vehicles which require high energy density, cycle durability and charge/discharge efficiency. Li-ion batteries have been used in many electronic devices since their production in 1990. The components of the cell are primarily the positive and negative electrodes and the electrolyte. The positive electrode is a metal oxide, negative electrode is made of carbon and the electrolyte is a lithium salt in organic solvent. The improvement in the performance of the battery can be done by the introduction of new materials with superb properties. Graphene which is one of the best materials discovered by humans has opened new possibilities in the field of lithium ion battery materials due to its light weight, high electrical conductivity, superior mechanical flexibility, and chemical stability.
Graphene can be used in both positive and negative electrodes of the battery. In the positive electrode, the cathode, it is used as a lithium metal oxide-graphene composites which enhance the electrochemical properties of the battery by increasing the diffusion kinetics of the lithium ion and improve the stability across a wide voltage range in crystalline oxide-graphene composites. In the negative electrode, the anode, the addition of graphene to anode materials has led to superior electrical conductivity, high surface area (2620 m2/g), high surface-to-volume ratio, and ultra-thin thickness. These excellent properties can shorten the diffusion distance of ions, structural flexibility, thermal and chemical stability which guarantee its durability in harsh environments1.
Reference:
1. Zhu, J., Duan, R., Zhang, S., Zhang, Y. & Zhu, J. Recent development of graphene in lithium ion battery electrode materials. Springerplus 3, 1–8 (2014).
Posted by Mohammed ZABARA on September 07, 2016
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