Executive Summary : | India is a major global energy consumer, and sustainable energy conservation methods are crucial to reduce fossil fuel use and greenhouse gas emissions. Electric vehicles hold great potential, and Li-ion batteries (LIBs) have revolutionized this industry. However, the toxicity and abundance of Li are significant concerns for India. Exploring battery chemistries using inexpensive, safe, naturally abundant, and environmentally benign materials can lead to more sustainable technology. Sodium resources are more abundant and cheaper than Lithium, but their specific energy is low compared to LiBs. The major critical component is the specific energy of SIB-compatible positive electrodes (PEs). Polyanion [Pa] phosphate [P] positive electrodes (PEs) have gained interest due to faster charging, longer stability, and safety of operation. However, the commercialized SIB, Na3V2(PO4)2F3 (NVPF), delivers a specific energy of 122 Wh/kg, which is required for an EV with a 500 km driving range. The environmental and economic concerns of PEs stem from the use of toxic Vanadium, which needs to be replaced with earth-abundant 3d transition metals like Ti, Mn, and Fe in PaPPEs. Combining two or more transition metals is attractive as it integrates the benefits of individual elements and addresses the problem of each in achieving high specific energy. The choice of PaPPE material is a trade-off between high specific energy, ease of synthesis, cost, safety, and charging rate. |