With anode breakthrough, America can commercialize this green energy storage opportunity.

As the global battery market looks beyond lithium, tin is emerging as a promising anode material for sodium-ion batteries, offering recyclability, affordability, and high theoretical capacity – significantly greater than graphite. By enhancing cost-efficiency, safety, and sustainability without substantial loss in energy density, tin-based anodes are helping narrow the performance gap with lithium-ion technology, though researchers still face the challenge of overcoming technical barriers to bring the material into commercial use.

Sodium-ion batteries (SIBs) are gaining traction, particularly in applications where cost and access to abundant raw materials are critical. Despite advantages like lower cost and environmental compatibility, SIBs have historically lagged in energy density compared to lithium-ion batteries (LIBs). Tin is emerging as a critical anode material that could help close that gap.

When tin reacts with sodium, it forms an alloy with a theoretical capacity far exceeding traditional hard carbon used in SIBs. This positions tin as a key enabler for boosting performance to levels that approach those of lithium-ion technologies, making SIBs more suitable for high-energy applications

A major benefit of sodium-ion batteries is the vast abundance and low cost of sodium, which reduces material expenses while improving resource security and sustainability. Though they are also safer and perform better at lower temperatures, one of the main hurdles has been their comparatively low energy density – particularly for electric vehicles. However, recent advancements are helping to make these batteries more competitive, with the first sodium-ion-powered EVs now entering production in China.

Leading experts from U.S. startup UNIGRID and Nanode Battery Technologies presented significant advancements highlighting tin's promising application in sodium-ion batteries at the International Tin Conference in Malaysia.

Bing Cao, CEO of Nanode Battery Technologies, described advancements in rapid charging tin anodes for sodium-ion batteries. The tin alloy anodes developed by Nanode achieved 94% capacity retention after six-minute charging and discharging cycles.

Benefits of tin-based

"When we think of batteries, we always imagine lithium-ion batteries, which are still expensive, unsafe, and have long payback times," said Darren Tan, Chief Executive Officer at UNIGRID, in an interview for Medium. "However, our advanced sodium-ion batteries offer a unique value proposition. Firstly, sodium-ion batteries are half the cost of lithium-ion batteries because of their immense abundance and low cost of materials. Secondly, our batteries provide safer non-flammable compounds. We want to eliminate fire hazard risks so people can safely use our batteries. Most importantly, we eliminate all critical materials, such as lithium, cobalt, and copper, and reduce its import reliance."

The use of tin as an anode material offers a compelling set of advantages, particularly in terms of performance. It can store more charge per gram than many other materials, resulting in batteries with higher energy density. Tin also has excellent volumetric density, making it especially beneficial for space-constrained applications such as portable electronics.

Beyond performance, tin's recyclability adds a meaningful sustainability advantage, aligning with the battery industry's broader push toward circular supply chains and reduced environmental impact.

"The United States set several ambitious goals, like dramatic carbon reductions and a net zero economy," said Tan. "To achieve all these goals by a certain date, we need terawatt hours of both renewable energy generation and battery storage. However, there's not enough lithium in the world to do this job. Thankfully, the United States is blessed with 90% of the world's sodium reserves, more than 1000 times more abundant than the entire world's lithium reserves. This presents us with a tremendous opportunity to use these resources to power our electric grid."

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With 90% of the world's sodium reserves, a resource more than 1,000 times as abundant as all global lithium combined, the United States faces a tremendous opportunity to leverage this supply to power the electric grid.

Interest and challenges

"The Inflation Reduction Act has opened up tremendous potential in the sodium-ion field," said Tan. "In lithium-ion batteries, lithium material will still need to be imported at some point upstream of the supply chain, be it during the mining, refining, or material production stage. Thus, there is a limit to which we can incentivize lithium domestic production. On the other hand, the raw materials for sodium-ion are readily available in the United States. As such, there is potential for us to establish the entire sodium supply chain domestically, and the IRA offers a lot of incentives for us to accelerate this process."

Growing interest in tin-based anodes has sparked a wave of research focused on balancing their high performance with complex material behavior.

Exploring a range of formulations from basic alloys to advanced composites, scientists have found tin sulfides – often paired with hard carbon to enhance conductivity and structural integrity – particularly promising for their electrochemical stability and controlled expansion, positioning these materials to help transition tin-based anodes from lab research to viable, scalable battery systems.

Despite its potential, tin faces significant technical hurdles in sodium-ion applications, including extreme volume expansion – up to 400% – that leads to mechanical stress, cracking, and anode degradation, as well as limited compatibility with carbonate-based electrolytes, which react unfavorably with tin to form unstable interfaces that further reduce battery lifespan.

To mitigate these challenges, researchers are developing strategies such as nanostructuring tin to increase surface area and accommodate volume changes, alloying it with other metals to buffer expansion, and forming tin-sulfur composites that enhance structural stability and overall performance.

With its high capacity, abundance, and recyclability, tin could help bring sodium-ion batteries into mainstream use – especially in applications like grid storage, energy balancing, and low-cost mobility.

While it may not completely close the performance gap with lithium-ion batteries, it narrows it significantly, making SIBs a strong candidate for markets where lithium is cost-prohibitive, scarce, or environmentally challenging.