Research Projects

Although lithium-ion batteries (LIBs) have dominated the global energy market, researchers are now investigating and highlighting the alternative battery chemistries due to their concerns about sustainability, geopolitical concentration of Li resources (particularly scarce resources in India), cost, and environmental hazards related to their disposal. Sodium-ion batteries (SIBs) are evolving as a potential substitute for LIBs in the quest for sustainable resource abundance and low-cost energy storage solutions. Layered transition metal-oxides, polyanionic compounds, Prussian blue analogues, and organic-based materials have been discovered so far for SIBs. The use of metal-based inorganic materials like metal complexes or salts as electrode materials prevails in energy storage systems (ESS); undoubtedly, their synthesis costs must be considered for large-scale storage. Thus, the research has been turned towards the augmentation of organic cathode materials (OCM), providing a versatile platform for developing a low-cost and readily available ESS option. Unlike inorganic materials, which are geographically restricted and have vast amounts of energy involved in their extraction and synthesis, this has given the rope to the growth of OCM for SIBs. OCMs are structurally diverse and can be designed and functionalized through various synthetic routes, simultaneously impacting their solubility, voltage, and capacity. Due to their sustainability and structural tunability, OCMs based on carbonyl, imine, organosulfur, and conductive polymer compounds have been investigated. Herein, ~C=O redox-active center-based Type I (1,4-TSAQ- 1,4-bis(tertbutyl thio) anthraquinone; 1,5-TSAQ- 1,5-bis(tertbutyl thio) anthraquinone;1,8-TSAQ- 1,8-bis(tertbutyl thio) anthraquinone) and Type II (1,5-DHAQ- 1,5-dihydroxyanthraquinone; 2,6-DSAQ- 2,6-disodiumsulfonate anthraquinone; 1,5-DS-2,6-DHAQ- 1,5-disodiumsulfonate 2,6-dihydroxyanthraquinone; 2,6-DS-1,5-DHAQ- 2,6-disodiumsulfonate 1,5-dihydroxyanthraquinone) OCMs have been proposed, which show a reversible 2e- redox process upon cycling. Molecular design with π-conjugated systems and electron-directing groups enhances the conductivity, facilitates electron movement, and can be applied for high-power-density SIBs. However, SIB must overcome challenges such as thermal stability, leakage, and poor cyclability when using volatile electrolytes. Therefore, polymer-based solid-state electrolytes (PSSE) address these challenges for long-term performance. Typically, a polymer matrix of polyethylene oxide (PEO), polyacrylonitrile, etc., with fillers to enhance ionic conductivity and mechanical strength has been reported. In the future, key aspects of designing such PSSE will be focused on, which may provide electrochemical stability and flexibility to the SIB. Widely, this proposal will focus on designing OCM for cost-effective, electrochemically stable, and PSSE in the future for flexible solid-state SIB devices.