The Case for Sodium-Ion Technology – Rethinking Battery Strategy in India

Why in News?

In recent days, the Sodium-ion batteries present a promising alternative to Lithium-ion batteries.

What are batteries?

• Battery – It is an electrochemical device that stores chemical energy and converts it into electrical energy to power devices.
• Components – It consists of one or more cells—containing an anode, cathode, and electrolyte—that produce electric current through chemical reactions.
• Cells vs. Battery – While a "cell" is the basic unit, a "battery" historically refers to multiple cells connected in series or parallel to increase voltage or capacity.
• Types of Batteries
  • Primary Batteries – Non-rechargeable, single-use batteries (e.g., alkaline).
  • Secondary Batteries – Rechargeable batteries (e.g., Lithium-ion, Nickel-metal hydride).

What are the issues with lithium-ion batteries?

• Dominance of Lithium-Ion Batteries – Among various battery chemistries such as lead-acid and nickel-cadmium, lithium-ion batteries have emerged as the dominant global technology.
• Their dominance is driven by high energy density, low self-discharge rates, and long cycle life.
• Sustained global investment over two decades has improved lithium-ion performance, manufacturing efficiency, and scale.
• By 2024, global lithium-ion manufacturing capacity reached nearly 2.5 times annual demand.
• Battery costs declined sharply from around $1,100 per kWh in the early 2010s to about $108 per kWh in 2025 due to economies of scale.
• Structural Challenges of Lithium-Ion Technology – Lithium-ion batteries are highly resource-intensive and depend on critical minerals such as lithium, cobalt, nickel, and graphite.
• The availability of these minerals is unevenly distributed across a limited number of countries.
• Refining and processing capacities are even more geographically concentrated.
• These factors create vulnerabilities related to supply security, price volatility, and geopolitical risk.
• Rising global battery demand is likely to intensify these constraints, necessitating alternative technologies.
• India’s Battery Manufacturing Ambitions and Constraints – India has taken steps to build domestic battery manufacturing capacity through the Production Linked Incentive scheme for Advanced Chemistry Cells launched in 2021.
• Around 40 GWh of battery manufacturing capacity has been allocated under the scheme so far.
• Actual deployment remains limited, with just over 1 GWh commissioned to date.
• India’s upstream ecosystem, including raw material extraction, mineral processing, and active material manufacturing, remains underdeveloped.
• Domestic lithium reserves are limited and not yet commercially viable.
• As a result, India’s dependence on imports for lithium-ion batteries is likely to continue.

How sodium-ion batteries serve as an alternative?

• Energy security – Sodium-ion batteries present a promising alternative that can reduce material risk and enhance energy security.
• Adjustable specific energy – Sodium-ion batteries have lower specific energy than lithium-ion batteries due to sodium’s higher atomic mass.
• However, this energy density gap can be narrowed by reducing the mass of other cell components.

Specific energy is defined as the energy per unit mass.

• Layered transition-metal oxide sodium-ion cathodes already demonstrate higher specific energy than other sodium-based chemistries.
• These sodium-ion batteries are approaching the specific energy of lithium iron phosphate batteries.
• Although volumetric energy density remains lower, ongoing optimisation is expected to reduce this gap further.
• Safety Advantages – Safety represents a major advantage of sodium-ion batteries over lithium-ion batteries.
• Studies show that sodium-ion cells exhibit significantly lower peak temperatures during thermal runaway events.
• Lithium-ion batteries are classified as dangerous goods and must be transported at a limited state of charge.
• These restrictions increase logistical complexity and costs due to safety risks associated with copper current collectors.
• Sodium-ion batteries use aluminium current collectors on both electrodes, avoiding such risks.
• Sodium-ion cells can be safely stored and transported at zero volts without performance degradation.
• Manufacturing Compatibility – Sodium-ion batteries are largely compatible with existing lithium-ion manufacturing infrastructure.
• Lithium-ion production lines can be adapted to sodium-ion manufacturing with relatively minor modifications.
• The main process difference lies in stricter moisture control during cell preparation.
• While sodium-ion cells require deeper vacuum drying, these challenges are expected to reduce with advancements in manufacturing techniques.
• This compatibility lowers capital investment barriers and enables manufacturers to hedge against supply risks.
• Lower Material Risk and Supply Chain Resilience – Sodium is derived from abundantly available resources such as soda ash, which are geographically widespread.
• Several sodium-ion chemistries eliminate the need for critical minerals like cobalt, nickel, and copper.
• Aluminium current collectors used in sodium-ion batteries are cheaper, lighter, and more widely available than copper.
• These features reduce exposure to commodity price volatility and improve supply chain resilience for India.
• Strategic Importance – Sodium-ion batteries are not merely experimental but are emerging as commercially viable technologies.
• Cost projections indicate that sodium-ion batteries could become cheaper than lithium-ion batteries by 2035.
• Around 70 GWh of sodium-ion manufacturing capacity is already operational globally as of 2025.
• Global capacity is expected to scale up to nearly 400 GWh by 2030.
• Early engagement with sodium-ion technology is therefore strategically important for India.

What lies ahead?

• Public support for battery infrastructure should explicitly include sodium-ion chemistries.
• Incentive frameworks should encourage flexibility so that battery plants can manufacture both lithium-ion and sodium-ion cells.
• Standards, safety codes, and certification pathways must be updated to include sodium-ion batteries.
• EV manufacturers should be encouraged to type-test and approve vehicle platforms using sodium-ion batteries.
• Targeted public funding for R&D, pilot projects, and early deployment should focus on grid storage and small EV segments.
• India’s growing reliance on batteries makes energy storage a strategic concern for economic and energy security.
• Continued dependence on lithium-ion batteries exposes structural vulnerabilities linked to critical minerals and imports.
• Sodium-ion batteries offer safety, material availability, manufacturing compatibility, and supply resilience advantages.
• By aligning industrial policy, regulation, and market incentives, India can build a future-ready battery ecosystem in which sodium-ion technology plays a central role.

Reference

The Hindu| Sodium ion Batteries