Italy: Sodium-ion narrows the gap with lithium-ion, says Polytechnic University of Turin professor

Sodium-ion batteries are rapidly closing the technological gap with lithium-ion, opening up new possibilities for large-scale energy storage. Yet how close are they really to commercial competitiveness?

pv magazine Italy had the pleasure of speaking with Silvia Bodoardo, a full professor at the Polytechnic University of Turin and scientific representative for the Batteries European Partnership Association (BEPA).

Bodoardo explains that state-of-the-art commercial sodium-ion cells have now reached around 175 Wh/kg, ensuring operation between -40 C and 70 C, with capacity retention of around 90% at -40 C. This comes at a time when very long cycle lives are becoming a reality for stationary systems and CATL plans to ship around 1 GWh of sodium-ion battery energy storage systems (BESS) within six months . The focus for sodium-ion batteries should be on the utility-scale segment.

What have been the main technological developments for non-lithium batteries over the last 12 months?

Sodium-ion technology clearly represents the most important development. The fundamental shift is no longer just about material performance, but the convergence of energy density, cycle life, safety, and manufacturability.

First, state-of-the-art commercial sodium-ion cells have now reached around 175 Wh/kg, compared to roughly 205 Wh/kg for advanced lithium iron phosphate (LFP) batteries. The gap is therefore becoming relatively small for stationary applications, where gravimetric energy density is not the dominant key performance indicator (KPI).

Second, CATL’s second-generation sodium-ion technology guarantees operation from roughly -40 C to 70 C, with a capacity retention of around 90% at -40 C.

Third, very long cycle lives are becoming a reality for stationary systems, with capacity retention exceeding 95% after 5,000 full-depth cycles in commercial-grade cells. The other major development is the emergence of chemical differentiation based on storage duration. Rather than seeing all technologies compete directly with lithium-ion, the market is starting to split into roughly two- to six-hour batteries and true long-duration energy storage (LDES) systems. For instance, vanadium redox flow batteries are progressing toward capacities in the tens or hundreds of megawatt-hours, and gigawatt-hour-scale systems have even been proposed. In short: non-lithium batteries are increasingly differentiating by application, with sodium-ion emerging as a direct competitor to LFP for multi-hour storage, while flow, zinc, and iron-air technologies are increasingly geared toward long-duration storage.

What have been the main commercial technological developments for non-lithium batteries over the last 12 months? And in Italy specifically?

In this context, sodium-ion battery figures are particularly interesting. CATL launched its sodium-ion BESS battery in June 2026 and expects cumulative shipments of around 1 GWh by the end of 2026, with international deliveries starting in 2027. In China, the transition is even faster. This is important because in 2025, global sodium-ion battery production was still less than 1% of lithium-ion production.

Europe is starting to follow this trend. Several EU startups such as Altris, Clarios, and InoBat reported in September 2026 that their European sodium-ion platform had successfully completed customer validation. Italy is at a much earlier stage on the sodium-ion commercialization curve, though cell manufacturers like FAAM have sodium-ion in their pipeline.

How much could sodium-ion BESS contribute to achieving Italy’s BESS targets?

Terna estimates that around 71.5 GWh of storage capacity will be needed by 2030, excluding existing pumped-storage hydropower plants. Under the National Integrated Energy and Climate Plan (PNIEC) scenario, around 50 GWh corresponds to new utility-scale storage facilities, alongside distributed systems and capacity market resources. Italy already had around 20 GWh of electrochemical storage in September 2026, meaning that additional storage capacity on the order of 50 GWh will still need to come online toward 2030, depending on the scenario and calculation scope used. The first MACSE (Energy Storage Capacity Procurement Mechanism) auction has already awarded 10 GWh, all based on lithium-ion batteries, scheduled for delivery in 2028.

The auction was heavily oversubscribed: bids were more than four times higher than demand, and the clearing price settled at around €13,000/MWh-year. An additional national requirement of 16 GWh for the 2029 delivery year was identified by Terna and approved in 2026.

In which segments (utility-scale, C&I, or residential)?

Where sodium-ion technology makes the most sense: utility-scale. Lower gravimetric and volumetric energy density matters little in a stationary facility with a duration of four to eight hours. Cycle life, safety, raw material availability, and levelized cost of storage (LCOS) are more important factors. The large portfolio of MACSE projects potentially makes Italy one of the most interesting test markets in Europe. The residential case is less convincing in the short term. Sodium-ion technology can work from a technical standpoint, but it presents a harder commercial proposition to justify because LFP technology is already cheap, compact, highly bankable, and backed by mature supply chains.