From Radiation Antidote to Battery Cathode: Udaipur's Macsen Energy Says Its Sodium-Ion Cell Has Passed 1,500 Cycles
Udaipur's Macsen Energy, spun out of a Prussian Blue drug-ingredient maker, says its Prussian White sodium-ion cell has passed 1,500 cycles in lab tests with about 90% capacity retained at 1,000 cycles, and plans a cathode scale-up facility and pilot cell line from 2027.
Most battery start-ups begin with a battery. Macsen Energy began with a medicine.
The Udaipur-based company reported on 6 October 2026 that its sodium-ion cell, built around a Prussian White cathode, has crossed 1,500 charge–discharge cycles in laboratory testing and retained about 90% of its initial capacity at 1,000 cycles. The results are company-reported and, as trade publications pv magazine and ESS News noted, independent third-party verification has not been disclosed. But they mark a step forward for one of the more unusual routes into India's battery-materials push.
A chemistry company's detour into energy storage
Macsen Energy grew out of Macsen Labs, a Udaipur specialty-chemicals manufacturer, and now operates as a separate energy-storage company. Macsen Labs produced Prussian Blue — the iron-cyanide compound best known as a pigment — as an active pharmaceutical ingredient. In medicine, Prussian Blue is used to treat internal contamination with radioactive caesium and thallium, because it binds those ions in the gut.
The same open, cage-like crystal structure that traps caesium ions can also host sodium ions. The reduced, sodium-rich form of the material, known as Prussian White, has attracted attention worldwide as a sodium-ion battery cathode. Macsen's team, already experienced in making the compound at pharmaceutical purity, turned its process know-how towards battery-grade material.
What the company is claiming
According to the company's announcement and trade-press coverage:
- Cycle life: the cell has crossed 1,500 charge–discharge cycles in laboratory testing, retaining about 90% of initial capacity at the 1,000-cycle mark.
- Cell design: a Prussian White cathode paired with a hard-carbon anode, a common combination for sodium-ion cells. The company says it is also exploring other anodes and anode-free designs.
- Cathode performance: Macsen cites a specific capacity above 150 mAh/g and coulombic efficiency of about 99.9% for its cathode material.
- Process: the cathode is synthesised in a single-step, single-vessel process under inert atmosphere, for which the company has filed a patent application. A July 2025 Macsen Labs release described this as a provisional patent.
Cycle life has been one of the main questions hanging over Prussian-type cathodes. The materials can trap water in their crystal lattice during synthesis, and residual water and structural defects are known to degrade performance over repeated cycling. Tight control of synthesis conditions — which is what a one-pot, inert-atmosphere process is intended to provide — is one route to addressing that.
The scale-up plan
Macsen says it has earmarked 10,000 square metres of land for a facility to scale up production of Prussian Blue analogue cathode material and to house a pilot line for sodium-ion cells, with construction expected to begin in 2027. pv magazine reported that the site location has not been disclosed.
That timeline has moved. In July 2025, Macsen Labs said it was advancing towards pilot-scale manufacturing and aimed for a pilot facility by early 2026. The current plan puts the start of construction in 2027 — a reminder that scaling battery materials from grams to tonnes is where many promising chemistries stall.
Why sodium-ion matters for India
Sodium-ion batteries do not need lithium, cobalt or nickel, the three materials at the centre of India's battery import dependence. Sodium is abundant and cheap, and Prussian White cathodes are made from iron, sodium and cyanide-complex chemistry rather than mined critical minerals. The trade-off is lower energy density than the best lithium-ion cells, which makes sodium-ion best suited to stationary storage, two- and three-wheelers and other applications where cost and safety matter more than weight.
That fit aligns closely with India's needs. The government is pushing large-scale battery storage to firm up solar and wind power, and DeepTech India has reported on proposals to make storage mandatory for new renewable projects and on a planned scheme to build domestic battery-material capacity. Every gigawatt-hour of storage built on locally made sodium-ion chemistry is a gigawatt-hour that does not depend on imported lithium-ion cells or refined lithium.
Macsen is not alone. Reliance has said its Jamnagar gigafactory will draw partly on the sodium-ion technology of Faradion, the UK company it acquired, and Pune's Rechargion Energy has had its sodium-ion cells validated by ARAI. What distinguishes Macsen's approach is its starting point: a company that already manufactures the cathode compound's parent chemistry at regulated purity, moving into batteries rather than a battery company sourcing cathode material.
What to watch
Three things will determine whether this result becomes a product:
- Independent validation. Lab cycling data from the developer is a starting point; third-party testing, ideally on larger-format cells, is what customers and investors will look for.
- Cell format and energy density. The announcement focuses on cycle life and cathode capacity. Full-cell energy density, rate capability and low-temperature performance will determine which markets the cell can serve.
- Execution on the pilot line. Construction beginning in 2027 means commercial volumes are still some way off. Holding to that schedule will be the clearest signal of progress.
For now, Macsen's announcement is a useful data point in a broader story: India's chemicals industry, long a supplier of pharmaceutical ingredients and specialty compounds, has the process skills that battery materials require. Turning those skills into domestic cathode supply is one of the less glamorous but more important pieces of India's energy transition.
Sources
- pv magazine — https://www.pv-magazine.com/2026/10/06/indian-startup-claims-over-1500-cycles-for-sodium-ion-cell-with-prussian-white-cathode/
- pv magazine India — http://www.pv-magazine-india.com/2026/10/06/indian-startup-claims-over-1500-cycles-for-sodium-ion-cell-with-prussian-white-cathode/
- ESS News — https://www.ess-news.com/2026/10/06/indian-startup-claims-over-1500-cycles-for-sodium-ion-cell-with-prussian-white-cathode/
- TaiyangNews — https://taiyangnews.info/technology/macsen-energy-reports-over-1500-cycles-for-sodium-ion-cell
- Saur Energy — https://www.saurenergy.com/solar-energy-news/udaipurs-macsen-energy-develops-sodium-ion-cell-with-prussian-white-cathode-12628188
- ThePrint (ANI press release) — https://theprint.in/ani-press-releases/macsen-energys-sodium-ion-cell-crosses-1500-cycles-in-testing-retains-90-capacity-at-1000-cycles/3062111/
- The Wire (PTI press release) — https://m.thewire.in/article/ptiprnews/macsen-energys-sodium-ion-cell-crosses-1500-cycles-in-testing-retains-90-capacity-at-1000-cycles
- The Tribune (July 2025 background) — https://www.tribuneindia.com/news/business/macsen-labs-achieves-breakthrough-in-sodium-ion-battery-chemistry-files-provisional-patent-and-advances-toward-pilot-scale-manufacturing
- Macsen Energy — https://www.macsenenergy.com/