Sodium metal chloride batteries are increasingly being chosen in the energy industry as a safer option than lithium-ion alternatives.
Data centres keep our digital world running, yet one of the most important parts of their infrastructure is often the least visible: the backup battery system.
As workloads grow and expectations around reliability tighten, many operators are taking a closer look at whether their traditional storage options can keep pace.
Increasingly, the answer is pointing towards sodium metal chloride (SMC) batteries, a technology built on chemistry that behaves very differently from the batteries most of us are familiar with.
Thermal runaway is the major risk that keeps data-centre engineers awake at night.
Lithium-ion batteries, for all their strengths, rely on flammable liquid electrolytes and reactive materials. Under the wrong conditions they can enter a self-heating spiral that’s fast, violent and extremely difficult to stop.
This isn’t what anyone wants in a room packed with servers and switching equipment.
SMC batteries operate differently. Their design centres around a solid ceramic electrolyte, known as β-alumina, which doesn’t burn or vent.
Inside the sealed cell, sodium metal forms the anode, nickel or iron chloride forms the cathode, and a molten salt electrolyte only becomes active when the battery is running. Because everything is contained within a rigid, high-integrity cell and the electrolyte itself isn’t flammable, there is no pathway for thermal runaway to occur.
Abuse testing has shown that even when these cells are crushed, punctured or short-circuited, they remain stable. For a data-centre environment, that’s a major advantage: the battery room doesn’t suddenly become a source of fire risk.
There’s also a common assumption that because SMC batteries operate internally at around 270–300°C, they must produce a lot of heat externally.
In practice, the opposite is true. The internal temperature is part of the chemistry, not a burden on the facility. The outer casing stays safe to touch, the batteries don’t contribute meaningfully to room heat load, and they don’t require active cooling. They also don’t vent gases or release pressure, even under challenging conditions.
For facilities already battling heat constraints or limited air-flow capacity, this stability removes a significant layer of operational stress.
The long service life of SMC batteries is another advantage, with the conversion between sodium metal and sodium chloride a straightforward, highly predictable reaction. It doesn’t generate the side reactions that commonly wear out lithium-ion or lead-acid cells – there’s no electrode swelling, no dendrite formation and no rapid electrolyte breakdown.
Because of this, SMC batteries routinely achieve a design life of around 20 years, with very little gradual decline in usable capacity. For data centres built around consistency and uptime, reducing the number of battery replacements over the life of the facility is a practical and financial benefit.
Despite their safety advantages, SMC batteries don’t force a trade-off in performance. Their nickel-based chemistry provides higher energy density than traditional lead-acid systems, while also reducing floor loading. And because the chemistry is non-flammable, the increase in stored energy doesn’t introduce extra fire load – an important distinction when operators are already dealing with strict building codes and limited plant space.
The environmental story is equally important for operators with strong ESG (environmental, social and governance) targets.
One of the standout features of SMC technology is its ability to be refurbished. Instead of discarding entire systems once their capacity tapers, the active materials can be replaced and the battery returned to service. This circular approach significantly reduces waste and makes the technology more aligned with modern sustainability expectations than many incumbent chemistries.
The move from theory to practice is already underway. Recently, Decon Corporation partnered with TPG Telecom to deliver a SMC battery system at TPG’s Perth data centre.
The installation proved how well the technology fits into a high-availability environment, delivering the combination operators are looking for: inherent safety, long-term stability and a predictable operating profile that supports the wider digital ecosystem. It’s a strong example of how collaboration can accelerate the adoption of safer and more responsible energy infrastructure in Australia.
As data-centre operators navigate growing energy demands, higher heat loads and stricter sustainability requirements, the choice of battery technology is becoming more consequential.
SMC systems bring together features that genuinely matter: they remove the risk of thermal runaway, deliver stable long-term performance, reduce environmental impact, and remain dependable across a broad range of operating conditions.
In a sector where downtime is unacceptable and risk margins are shrinking, this chemistry offers a steady, sensible and future-ready way forward.
This feature appeared in the March edition of Energy.
