Rethinking battery strategy in India: the case for sodium-ion technology

Batteries have become deeply embedded in modern life. From laptops, mobile phones, wearable devices such as smartwatches and wireless earphones, to power tools, electric vehicles (EVs), and large-scale battery energy storage systems, batteries now underpin both personal convenience and critical infrastructure. A newer trend is also emerging, with batteries being integrated directly into household appliances, ranging from induction cooktops to refrigerators, alongside the rise of energy storage systems. These developments collectively point to a future saturated with batteries, making energy storage a foundational pillar of economic growth, energy security, and the clean energy transition. Among the various battery chemistries that have existed or are still in use, such as nickel-cadmium, lead-acid, and others, lithium-ion batteries have emerged as the dominant global technology. This dominance is largely driven by their high energy density, low self-discharge rates, and long cycle life. Sustained global focus on lithium-ion technology over the past two decades has resulted in steady improvements in performance, manufacturing efficiency, and large-scale capacity build-out. By 2024, global lithium-ion manufacturing capacity had reached nearly 2.5 times annual demand, further accelerating cost reductions through economies of scale. As a result, costs have fallen dramatically, from nearly $1,100 per kWh in the early 2010s to about $108 per kWh in 2025. However, the success of lithium-ion batteries masks several structural challenges. These batteries are highly resource-intensive and depend on critical minerals such as lithium, cobalt, nickel, and graphite. The availability of these materials is unevenly distributed across a handful of countries, while refining and processing capacities are even more geographically concentrated. This creates vulnerabilities related to supply security, price volatility, and geopolitical risk. As global demand for batteries accelerates, these constraints are likely to intensify, reinforcing the need for alternative technologies that can support a more resilient and equitable energy transition. India provides a compelling case for rethinking battery technology choices. The Government of India has made sustained efforts to build domestic battery manufacturing capacity, most notably through the Production Linked Incentive (PLI) scheme for Advanced Chemistry Cells launched in 2021. Under this scheme, around 40 GWh of manufacturing capacity has been allocated so far. While this represents meaningful progress, deployment remains at an early stage, with just over 1 GWh commissioned to date and additional capacities expected to come online gradually. More critically, India’s upstream ecosystem, from raw material availability and mineral processing to cathode and anode active material production and separator manufacturing, remains underdeveloped. Domestic reserves of lithium are limited and yet to be proven commercially viable, while processing infrastructure is still nascent. Consequently, import dependence for lithium-ion batteries is likely to persist for a considerable period. This reality underscores the importance of parallel investments in alternative battery technologies that can reduce material risk and strengthen long-term energy security. Sodium-ion batteries (SiBs) represent one such technology, offering significant promise for India in the medium to long term. From a fundamental perspective, sodium-ion batteries exhibit lower specific energy (Wh/kg) than lithium-ion batteries, largely because sodium has a higher atomic mass than lithium, which intuitively leads to more mass per unit of stored energy. However, this performance gap is often overstated. In practice, it can be significantly narrowed if the mass of other cell components in sodium-ion batteries is reduced, thereby compensating for the higher mass of sodium itself. Moreover, among commercially available sodium-ion chemistries, layered transition-metal oxide cathodes already deliver higher specific energy than polyanionic compounds and Prussian blue analogues, underscoring the growing competitiveness of sodium-ion technology. Importantly, layered oxide sodium-ion batteries are now approaching the specific energy of lithium iron phosphate (LFP) batteries, as illustrated in Figure 1. Although their volumetric energy density (Wh/L) still trails that of LFP, ongoing materials and cell-level optimisations are expected to substantially narrow this gap and potentially lead to meaningful overlap. It is also important to emphasise that this comparison is based on commercially available products, whereas laboratory-scale and pilot-level research results suggest even greater performance potential. By contrast, comparisons with high-energy lithium nickel manganese cobalt (NMC) chemistries are less instructive, as NMC batteries occupy a distinct performance space and entail separate trade-offs related to safety and reliance on critical minerals. Safety is one of the most compelling advantages of sodium-ion batteries. Studies, including those conducted by the U.S. Naval Research Laboratory, have shown that sodium-ion cells exhibit significantly lower peak temperature rise during thermal runaway events compared to lithium-ion cells. This intrinsic safety advantage extends well beyond cell performance into storage, handling, and transportation. Lithium-ion batteries are classified as “Dangerous Goods” by national and international transport authorities, necessitating strict packaging, handling, and transportation requirements. They are typically shipped at a state of charge not exceeding 30%, which increases logistical complexity and cost. These restrictions stem from the use of copper current collectors on the anode side, which can dissolve at low voltages and redeposit on the cathode, increasing the risk of internal short circuits. Sodium-ion batteries do not suffer from these limitations. They use aluminium current collectors on both the anode and cathode sides, as sodium does not form unstable alloys with aluminium. As a result, sodium-ion cells can be safely stored and transported at zero volts without degradation or safety risks. Prolonged storage at zero volts has been shown not to compromise cycling stability. This feature offers significant benefits across the value chain, including safer handling, lower transportation costs, and greater flexibility in manufacturing and installation. Another critical advantage of sodium-ion batteries is their compatibility with existing lithium-ion manufacturing infrastructure. With relatively minor modifications, lithium-ion production lines can be adapted to manufacture sodium-ion cells. This dramatically lowers the capital barrier to adoption and allows manufacturers to hedge against raw material supply risks. The primary process difference lies in moisture sensitivity during cell stack preparation. Sodium-ion batteries require more stringent vacuum drying conditions, as residual moisture can have a greater negative impact on performance. While lithium-ion cells can tolerate drying at relatively mild vacuum levels, sodium-ion cells require deeper vacuum conditions, which may marginally increase energy consumption and manufacturing costs. However, as the industry progresses toward dry electrode coating and advanced manufacturing techniques, these challenges are expected to diminish. Sodium-ion batteries offer a structurally different material pathway compared to lithium-ion systems. Sodium is derived from abundantly available resources such as soda ash, which are far more plentiful and geographically diversified than lithium. Several sodium-ion chemistries eliminate the need for critical minerals such as cobalt, nickel, and copper altogether. In addition, sodium-ion batteries use aluminium as the current collector for both electrodes. Aluminium is cheaper, lighter, and more widely available than copper, resulting in cost savings and weight advantages. These material choices significantly reduce exposure to global commodity price volatility and enhance supply chain resilience, a critical consideration for a country like India. Taken together, these attributes suggest that sodium-ion batteries are not merely an experimental technology but a commercially viable and strategically important solution. Cost projections indicate that sodium-ion batteries could undercut lithium-ion batteries by 2035. As of 2025, around 70 GWh of sodium-ion manufacturing capacity is already operational globally, with expectations of scaling to nearly 400 GWh by 2030. This rapid expansion highlights the urgency for India to engage early and decisively with this technology. To ensure sodium-ion batteries become a meaningful part of India’s energy storage landscape, a coordinated policy and regulatory approach is essential. Public support for upstream battery infrastructure, such as cathode, anode, electrolyte, and separator manufacturing, should explicitly include sodium-ion chemistries rather than remaining narrowly focused on lithium-ion systems. Future incentive programs, including revisions to the PLI framework, should encourage flexibility, ensuring that new battery plants are designed to accommodate both lithium-ion and sodium-ion production with minimal retrofitting from the very beginning. From a regulatory standpoint, standards, safety codes, and certification pathways must be updated to explicitly include sodium-ion batteries, enabling faster commercialisation and deployment. EV manufacturers should be encouraged through procurement policies, pilot programmes, and regulatory nudges to type-test and approve vehicle platforms using sodium-ion batteries alongside lithium-ion options. This dual-approval strategy would allow rapid substitution in response to supply disruptions or cost fluctuations. Finally, targeted public funding for R&D, demonstration projects, and early deployments, particularly in grid storage, two- and three-wheeler EVs, and stationary applications, can help build market confidence. By aligning industrial policy, regulation, and market incentives, India can foster a fair, resilient, and future-ready battery ecosystem in which sodium-ion batteries play a central role. Jaideep Saraswat leads the Electric Mobility vertical at Vasudha Foundation where he focuses on addressing key barriers to EV adoption and advancing sustainable mobility solutions; Nikhil Mall is also part of the Electric Mobility vertical contributing to research, stakeholder engagement, and initiatives that promote the transition to clean transportation science (general) / India / Text and Context / The Hindu Explains