Engineered Carbon Nanomaterials as Anode Material for High-Performance Na-ion Batteries

Electrical energy storage is one of the most critical needs of 21st century. At present, among various energy storage technologies, Lithium (Li)-ion batteries have conquered the portable electronic market. They have also proven suitable for next generation large scale energy storage (electric vehicle) due to their high energy density and remarkable cyclic life at higher currents. However, Li-ion batteries are expensive due to the heavy capital investment needed in mining and extraction of Li. Li is unevenly distributed in earth crust which is a critical barrier to the scale-up of Li production and thus Li battery energy storage for large-scale applications such as electrical vehicles remains limited. In this perspective, replacing expensive Li based electrodes with a sustainable battery electrode material is a major challenge to meet the increasing demand for portable electronics and zero emission vehicles. Li based active material electrodes and electrolytes may be replaced with the abundant alkaline element in earth’s crust with similar characteristics. In this direction, sodium (Na) based rechargeable batteries have been demonstrated with similar energy storage mechanism in 1980. However, Na-ion cells will always fall short of energy density compared to Li-ion batteries due to large atomic size compared to Li. This large atomic size not only results in lower energy density, it also limits the intercalation of Na into layers of graphite. Increasing surface area and electronic conductivity for improved specific capacity with good cyclic performance is a key challenge for commercialization of Na-ion batteries.