Seventy times faster charging possible for Lithium-ion batteries 

A research team from the Netherlands and the UK have used MAX IV to investigate a material that could make charging of lithium-ion batteries seventy times faster than today. It is a promising development for future electric vehicles and renewable energy.

Batteries have an important role to play in a sustainable society. Lightweight, fast-charging batteries open for further utilisation of electric vehicles and renewable but non-continuous energy sources, which require efficient storage to be competitive. Battery research is focused on two tracks: inventing entirely new battery technologies or further developing the lithium-ion batteries that are the most commonly used type of battery today. In the current project, the research team have used MAX IV to investigate a new electrode material for lithium-ion batteries.

“We remain interested in researching lithium-ion batteries over new technologies due to a number of factors,” says Maarten Jager, PhD candidate at the University of Groningen and one of the study’s authors.” The technology readiness level of lithium-ion batteries is very high. In the rechargeable battery market, lithium-ion batteries account for about 67% of the market share. The chemistry involved in lithium-ion batteries is also quite well-known, so there is a more straightforward path to explore new components, which could easily be implemented into the market. New technologies can often be promising, but still take years to be developed enough.”

One of the components of batteries that can be further optimised is the electrode material. The general material for the anode, the negative electrode, in lithium-ion batteries is graphite. 

“Graphite has a relatively good stability, high conductivity, and low cost. However, it also has a number of major drawbacks, which reduce its performance. It has a chemistry that limits the amount of energy each unit can store and is flammable. However, its most important drawback is the amount of power it can deliver. Graphite cannot release and store energy quickly, as it would break the electrode,” says Jager. “One major threshold consumers have for choosing an electric car is the time it takes to fully charge it at a fuel station, often over 20 minutes. Significantly bringing down this charging time without compromising battery life or storage capacity is impossible with graphite. Our experiments show that by replacing graphite with copper niobate, we can, without compromising, charge the battery 70 times faster than graphite.”

The copper niobate the researchers used in their experiment is a special so-called mixed crystal phase copper niobate containing five different crystal structures. It is the first time this type of copper niobate is investigated as a battery electrode material. Generally, so-called pure phase materials containing only one crystal structure have been thought to be the best alternative for batteries, but the new results challenge this idea.

Read more on MAX IV website

New process makes battery production more eco friendly

Switching from gas-powered cars to electric vehicles is one way to reduce carbon emissions, but building the lithium-ion batteries that power those EVs can be an energy-intensive and polluting process itself. Now researchers at Dalhousie University have developed a manufacturing process that is cheaper and greener.

“Making lithium-ion cathode material takes a lot of energy and water, and produces waste. It has the biggest impact on the environment, especially the CO2 footprint of the battery,” says Dr. Mark Obrovac, a professor in Dalhousie University’s Departments of Chemistry and Physics & Atmospheric Science. “We wanted to see if there were more environmentally friendly and sustainable – and less expensive – ways to make these materials.”

Most electric vehicle batteries use lithium nickel manganese cobalt oxide (NMC), with the elements mixed in the crystal structure of the cathode. They are typically made by dissolving the elements in water then using the crystals that form when the elements come together as a solid. That process takes a lot of water – which then has to be treated to clean it – and energy, which is the main source of the cost and carbon footprint of the batteries. Using the Canadian Light Source (CLS) at the University of Saskatchewan, Obrovac and his team investigated whether they could use an all-dry process to get the same results while saving energy, water, and money.

Their work has been published in two papers, in ACS Omega and the Journal of the Electrochemical Society.

“We wanted to see, can you get the same quality if you take dry materials and combine them using simple processes that you’d find in any large-scale factory and heat them up,” he says. “And under what conditions can you do that to get commercial-grade material while cutting out the water and the waste?”

Cathodes made from dry materials are sometimes not as homogeneous as those made in water, so the team tried a variety of methods using different oxides and heating regimes under different temperatures and pressures to determine what worked best.

Read more on CLS website

Image: A student making lithium batteries in a glove box for the evaluation of new cathode materials.

Credit: CLS