Storing for the future – battery chemicals

Battery technology is now an area with significant R&D resources being poured into it. Muriel Axford finds out how chemical companies are among the leaders in developing the new generation of materials needed to store the energy required for powering thousands of products, from mobile phones and medical devices to cars.

Significant investments in battery technology

November 2011 saw BASF announce it was creating a "new global business unit" bringing together its current and future battery-related electromobility activities. From January 1 2012, BASF's Battery Materials business unit will integrate the existing battery activities of the company's catalyst division, its intermediates division and BASF Future Business.

"The lithium-ion battery is currently the power source of choice for both small and large-scale applications."

Dr Andreas Kreimeyer, a BASF member of the board of executive directors and research executive director, said: "The creation of the global operating unit, Battery Materials, will allow us to take a more integrated solution-oriented approach to serving battery manufactures, leveraging our resources and expertise in a unified and focused manner."

The establishment of a business unit devoted to battery technology follows hot on the heels of the opening of the Battery and Electrochemistry Laboratory (BELLA), a collaboration between BASF and the Karlsruhe Institute of Technology (KIT).

The laboratory links the electrochemistry expertise of BASF with KIT's research capabilities. The laboratory is aimed at accelerating the implementation of research results for high-energy battery systems.

The creation of the new division and the opening of the laboratory are part of ongoing strategy by BASF to "make decisive contributions to the mobility of tomorrow." Such is the nature of the drive to develop battery technology of the future; companies are reluctant to divulge the exact amounts which are being invested.

During the first quarter of 2011 the chemical major announced it would be investing a "three-digit million sum" for battery related activities. As well as BASF's own R&D programmes and work with partners, the investment also includes the construction of a facility for the production of advanced cathode materials. Being built in Ohio, US, the facility will supply cathode materials for the manufacturing of high-performance lithium-ion batteries. The plant is scheduled to become operational in 2012.

Other chemical majors investing to improve battery technology include Dow Kokam. The company was established during 2009 to develop and manufacture advanced energy storage technologies for transportation and other industries. The company is owned by Dow Chemical, TK Advanced Battery and Groupe Industriel Marcel Dassault.

During October 2011, Dow Kokam officially opened its global R&D centre located in Lee's Summit, Missouri, US. The company said that the facility would allow it to bring next-generation lithium-ion battery solutions to market faster, increase battery performance and reduce their overall cost.

Government investments

Underlining the importance of the need to develop improved energy storage solutions, R&D efforts are also being backed by serious investment from government.

During the final quarter of 2011 the US Department of Energy's research centre, Argonne National Laboratory, announced it had established a number of partnerships to advance the development of battery technology.

Collaboration with Dow Chemical Company will see the partners carry out research on advanced battery technologies. The focus will be on improving the performance, cost competitiveness and eventually the adoption of several energy storage materials.

At the same time, Argonne announced it was working with Western Lithium to develop lithium carbonate for multiple battery applications. Western Lithium said its collaboration with Argonne is intended to develop lithium specifications suitable to engage potential customers for lithium carbonate off-take agreements.

Improving lithium-ion battery performance, the power source of choice

The lithium-ion battery is currently the power source of choice for both small and large-scale applications from laptop computers, cameras and mobile phones, through to electric cars. But they have some limitations, including deterioration over time as well as the fact that the increasingly energy hungry applications mean the batteries can need charging after just a few days.

"Sodium-based technology possessed a number of benefits which lithium-based energy storage couldn't capture."

Much research is now focused on developing better performing batteries which use solid state electrolytes containing thermally stable ionic liquids, along with nano-structured anodes and advanced cathodes.

Indeed, in the area of electrolytes, again the chemical major BASF is making advances. During May 2011 the company announced it had established a global electrolytes team in its intermediates division. Electrolytes are complex formulations essential for the transport of electronic charge within a battery, and high quality electrolytes are a prerequisite for improving battery performance.

"In the electrolytes business we intend to become a system supplier that is capable of offering tailor-made solutions to our customers," said Kreimeyer.

Suitable cathode materials are also a requirement in the adoption of electric vehicles. The relatively short distance that a car can travel before it needs recharging is perhaps the most pressing issue related to electric vehicles. BASF has released a cathode material for lithium-ion batteries which allow higher energy density, safety and efficiency, enabling increased driving distances for full electric, plug-in or hybrid vehicles with reduced battery pack weight.

Dr Kirill Bramnik, global product technology manager at BASF, said: "Cathode composition, structure and morphology influence battery power and energy density. New cathode materials show significant improvements in these key attributes."

Dr Phillip Hanefeld, global marketing and strategy manager BASF battery materials, added: "BASF products and research activities are substantially contributing to the effort to make electric cars affordable and sustainable. A key focus is on improving battery performance going forward."

Investigating the potential of sodium-ion

Improvements in lithium-ion batteries are set to make a huge impact on energy storage in the near future. But Argonne National Laboratory is also looking at new elements that could potentially prove to be an important alternative to lithium with sodium-ion technology attracting attention.

Argonne Chemist, Christopher Johnson, who is also leading the work to improve the performance of ambient-temperature sodium-based batteries, said that sodium-based technology possessed a number of benefits which lithium-based energy storage couldn't capture.

"During October 2011, what is said to be the world's first liquid air energy storage system went into operation."

But perhaps more importantly, Johnson pointed out, is the fact that sodium is far more naturally abundant than lithium, which makes sodium lower in cost and less susceptible to extreme price fluctuations as the battery market rapidly expands.

"Our research into sodium-ion technology came about because one of the things we wanted to do was to cover all of our bases in the battery world. We knew going in that the energy density of sodium would be lower, but these other factors helped us decide that these systems could be worth pursuing."

While the drawbacks are likely to rule out sodium-ion batteries for transportation applications, as the weight of such batteries would be an issue, they could find application where the storage was stationary.

"The big concerns for stationary energy storage are cost, performance and safety, and sodium-ion batteries would theoretically perform well on all these measure," said Johnson.

Johnson is working with a group led by Argonne nano-scientist Tijana Rajh to investigate how sodium-ions are taken up by anodes from titanium dioxide nanotubes.

Storing excess energy

In the meantime, energy storage solutions are moving into the big time. During October 2011, what is said to be the world's first liquid air energy storage system went into operation. Located in Berkshire, UK, the storage system is set be become an answer to a problem faced by many power grids - what to do when too much energy is generated by wind turbines.

The storage facility is owned by Highview Power Storage, a UK energy storage development company. Connected to the grid, the system can be scaled to 1000MWs/GWhs of storage.

Highview said that during September 2011 wind farm operators were paid nearly £3million to switch off their wind farms, and then traditional generators were paid peak prices to turn their gas and oil generators on at periods of high demand.

Highview said it was now looking to move towards deploying a full scale commercial plant with appropriate partners.