Lithium is Good, But What Are Some Better Battery Alternatives?

This article is part of our series on responsible mining solutions. The push for clean energy is fueled by a growing demand for minerals, but conventional mining has a track record of harmful social and environmental impacts. Lithium-ion battery alternatives are another potential solution to that problem.

Lithium-ion batteries are currently the best combination of price, performance and sustainability on the clean energy battery market. Exploring those attributes separately, lithium-ion batteries are not the cheapest, nor the highest performing in all battery categories, or the most sustainable option. They are acceptable in all three categories, but there is room for improvement.

“There’s a strong need to diversify our battery chemistries,” said Magda Titirici, the chair of sustainable energy materials at Imperial College London. “There’s no one solution. There’s one type of battery if you need high power. There’s another type if you need long duration. The needs for batteries are very diverse.” 

Lithium extraction is a water-intensive process that usually happens in arid regions. As such, communities in Argentina, Chile, Bolivia, and Serbia have all put up fights to prevent international mining companies from entering their territories.

Let’s explore the other options, starting with a battery alternative that uses an easily sourced and readily available mineral that does not have extraction complications like lithium.

Sodium-ion batteries

At this point, sodium-ion batteries represent the most promising alternative to lithium batteries. JAC, a Chinese automaker, already has electric vehicle (EV) models on the market powered by sodium-ion batteries. 

Also in China, a 10-megawatt-hour sodium-ion energy storage station became operational earlier this year, with plans to expand to 100 megawatt hours. That could meet the electricity needs of 35,000 residents and avoid 50,000 tons of carbon dioxide emissions.

In terms of performance, lithium batteries pack a slightly stronger punch. But sodium is much more abundant in the Earth’s crust than lithium, and it can be extracted from seawater at a low cost, providing a more sustainable alternative.

“The advantage of sodium is the availability of the materials,” Titirici said. “And the choice of cathodes is based on very abundant materials with no critical metals.”

In sodium-ion batteries, there is also no threat of thermal runaway, meaning a safer battery that is not prone to fires, unlike lithium-ion batteries.

If manufactured on a similar scale, sodium-ion batteries would be cheaper to produce than lithium-ion batteries. Right now, however, sodium-ion batteries are still more expensive.

“Despite the availability of the materials, there is no market for sodium, so cost is a barrier,” Titirici said.

Environmental and social impact: Sodium is far more abundant than lithium and much more easily extracted. There are huge salt deposits around the world, often in less fragile environments than where lithium is found. Also, sodium-ion batteries do not require mining cobalt.

Zinc-air batteries

Zinc-air batteries are safer than lithium and have a higher energy density meaning they can hold more energy for longer. But a current challenge is crystalline masses forming on the zinc part of the battery that hinder the battery’s performance.

While they can store energy better than a lithium battery, the amount of power they can produce is lower.

“Zinc batteries are safer and have high theoretical energy density,” said Muhammad Azhar, engineering lecturer at Edith Cowan University. “And recycling zinc batteries seems easier than lithium, but both are in the developmental stage.”

Zinc is cheaper than lithium. Over the past five years, battery-grade zinc cost between $1.85 and $4.40 per kilogram. Battery-grade lithium, on the other hand, fluctuated between $5.80 and $80 per kilogram.

The most promising applications of zinc batteries lie in energy storage and long-term, low-energy applications like watches or hearing aid batteries.

Environmental and social impact: Zinc is far more abundant than lithium and much easier to extract.  While there are hazardous impacts of mining zinc, it is generally a friendlier process than extracting lithium. Zinc deposits are more plentiful and are found in less environmentally sensitive regions than lithium.

Nickel-zinc batteries

There’s nothing new about nickel-zinc batteries. Invented by Thomas Edison in 1901, the battery didn’t gain the same traction as some of Edison’s other inventions like the record player, movie camera or light bulb. 

Its ability to discharge high amounts of power quickly makes it ideal for mission-critical applications, like backup power for data centers or telecommunications networks. While nickel-zinc batteries don’t match the performance output of lithium batteries, they are very safe and cheaper to produce.

Environmental and social impact: Nickel and zinc are much more available than lithium. Of course, legacy mining issues can present problems in the extraction of either, but overall, they are more sustainable options compared to lithium.

Multivalent batteries

Aluminum, magnesium, calcium and zinc are metals that can form ions that carry multiple positive or negative electric charges. Batteries store and release energy through the movement of these ions. 

In a lithium-ion battery, one lithium-ion molecule carries one charge of electricity. In multivalent batteries, each ion carries multiple charges of electricity. That doesn’t mean more power, but that means they could store more energy and hold their charges longer than lithium batteries. 

“It is very early days, so it’s unlikely that there is interest from any companies or customers in multivalent,” Titirici said. “They could be very interesting if we could make them work, but as I said, it’s early days.”

Environmental and social impact: Extracting and processing aluminum, magnesium and zinc are not light processes. Each can carry significant energy use, land disturbance and social impact challenges. Calcium extraction generally has a lower environmental impact. One advantage that aluminum has, however, is that it is very easily recycled. Using recycled aluminum in multivalent batteries could offer a sustainable solution.

Redox-flow batteries

“Redox flow batteries are based on two massive tanks where electrolytes are flowing, Titirici said. “We won't see those in EVs, but definitely for stationary storage they are a viable solution.”

These battery systems used the rare metal vanadium in the past, but researchers are exploring other options that require less expensive, easier-to-obtain components like iron.

“Vanadium is very expensive and a critical metal, so people are looking at other alternatives to vanadium,” Titirici said.

Social and environmental impact: Redox flow batteries are an improvement over fossil fuel storage systems in terms of carbon emissions, but vanadium is not the friendliest mineral to extract. Iron, while cheaper, is a carbon-intensive product. These options, however, offer significant environmental improvements over fossil fuel-based storage systems.

Solid-state batteries

“The solid-state battery works exactly like a lithium-ion battery, but in a lithium-ion battery, you normally have a liquid electrolyte that shutters lithium ions between anode and cathode,” Titirici said. Anodes and cathodes are the negative and positive conductors in a battery, respectively, that allow for charging and discharging. The electrolyte is the substance the ions move through as a part of that process. 

In solid-state batteries, that electrolyte is solid. This allows for a greater energy density than regular lithium-ion batteries which means, for example, that EVs with solid-state batteries could travel further distances between charges.

Solid-state batteries also have a higher cycle life, are more easily recycled and safer, and should be a more sustainable option.

What’s the catch? They’re expensive to produce, but as supply chains and processes become established, those costs should come down.

“They will be quite expensive,” Titirici said, “But I think we will see commercial lithium solid-state batteries on the market.”

Environmental and social impact: Lithium is still used, but solid-state batteries can avoid critical minerals like cobalt and nickel. Earlier this year, researchers developed the design principles for the world’s first sodium solid-state battery. It’s early, but this could be a major breakthrough in batteries combining performance, safety and sustainability.

Lithium-sulfur batteries

Quick, high energy output is what lithium-sulfur batteries offer. This is not practical for the majority of applications, but there are cases where it is the desired result.

“Lithium-sulfur batteries can be commercialized for very niche applications like drones or military or things like that,” Titirici said. “They are going to be very expensive because it's a very niche market, but we will see lithium-sulfur commercial products.”

There are also sodium-sulfur batteries, but these are a bit behind lithium-sulfur in terms of market readiness.

Environmental and social impacts: These batteries still require lithium, but they offer lower carbon footprints than current fossil fuel-based uses. And sulfur is a much lower-impact mineral than lithium-ion components like cobalt and nickel.

Organic batteries

“Organic materials are weak, and they can't withstand very high voltages that are needed in a battery,” Titirici said. “They have very low energy densities in general.”

That said, organic batteries can be used in low energy density applications like chips or sensors.

Just because they are organic, does not mean they are green and environmentally friendly. They use carbon compounds that can be toxic but can come from renewable sources that do not require harmful mining practices.

Environmental and social impact: These batteries offer one of the lowest environmental and social impacts of all batteries. While toxicity can be a concern, organic batteries are less harmful to the environment and humans than other battery compositions, overall. This is the most sustainable option that we explored.

Cleaner batteries, cleaner future

While lithium-ion may be the track star for now, using alternatives where possible can complement its efforts and lower the environmental and social impact that lithium-ion batteries carry. As research efforts continue, we should see more commercial products using the battery chemistries mentioned above, and more sustainable chemistries emerging in laboratories.