As next-generation energy storage devices, new cathode materials can be used to create high-performance, cost-effective, and environmentally friendly Na-ion batteries
Scientists have discovered a way to address the air/water instability and structural-cum-electrochemical instability of Sodium-transition-metal-oxide-based cathode materials for Sodium-ion batteries at the same time, and as a result, they developed new air/water-stable stable and high-performance cathode materials. The newly developed materials have high electrochemical cyclic stability and stability when exposed to air/water, allowing for the development of systems that are expected to serve as cost-effective and sustainable energy storage systems for a variety of applications, including consumer electronic devices, grid energy storage, storage of renewable energy, and, eventually, electric vehicles.
As the relevance of battery-powered electric vehicles grows owing to climate and environmental concerns, the development of a cost-effective, resource-friendly, safe, and sustainable alkali metal-ion battery system that is superior to the Li-ion system is critical. Because India has an abundance of Na-sources, the future Na-ion battery technology will be particularly essential in the Indian context. A Na-ion cell, like any other alkali metal-ion battery cell, has cathode and anode active materials (supported by metallic current collector foils) that allow for reversible insertion/removal of the charge carrier (viz., Na-ion) during cell charge/discharge. The cathode material serves as the Na-reservoir in such a cell, with cell performance determined by the structural/electrochemical stability of the electrodes, Na-transport kinetics, and different resistances (which are dynamic in nature).
Despite the many advantages of Sodium-ion batteries, the electrochemical behavior/performances of the 'layered' Na-TM-oxide-based cathode materials, as well as their stability when exposed to moisture, require significant improvements before widespread development and use of Na-ion battery systems for a variety of applications becomes a reality. Because of their lack of stability, Na-TM-oxides are difficult to handle and store, and their electrochemical performance suffers as a result. Furthermore, the water instability necessitates the use of toxic-hazardous-cheap compounds such as N-Methyl-2-pyrrolidone (NMP) for electrode preparation, as opposed to the possibility of using water-based slurries.
In order to overcome this difficulty, Prof Amartya Mukhopadhyay's group at IIT Bombay used materials science and electrochemical principles in their recent research to identify the main factors and governing parameters that can assist produce high-performance Na-ion batteries. They developed a universal design criterion in their research, which was supported by the Science and Engineering Research Board (SERB), an attached institution of the Department of Science and Technology (DST), and the DST's Materials for Energy Storage scheme, paving the way for successful design and widespread development of environmentally stable and high-performance cathodes for the sustainable Na-ion battery system and beyond.
In a work published in the journal Chemical Communications, the researchers proposed a change in the alternate slab layered structure of the Na-TM-oxide structure of the Na-ion battery cathode by introducing "interslab" gap by modifying the TM-O bond covalency.