Growth in energy harvesting for ceramics picking up speed

By Paul Rackstraw
Published: Saturday, 21 May 2016

The increased uptake of EVs and the growing interest in various types of battery components is fuelling demand for ceramics in energy harvesting, which so far has accounted for a fraction of the industry. Kasia Patel

The use of ceramics in glass for energy harvesting and storage is set to grow over the next few years, attendees at the Ceramics Expo held in Cleveland, Ohio heard in May. 

According to Susan Troiler-McKinstry, professor of Ceramic Science and Engineering at Penn State University, 43% of the world’s EVs were bought in 2014, fuelling an interest in downsizing energy components by increasing energy density. 

 "Electro ceramics are of interest for solar, mechanical and thermal energy harvesting," Troiler-McKinstry added.

This, she said, means that industrial mineral-consuming industries such as thin glass are being developed for their high dialectric energy storage and stabilising properties.

Additional developments in ceramic energy storage technology are becoming necessary for use in solid state capacitors, electrolytic capacitors, ultra-capacitors, Li-ion batteries, Pb-acid batteries and fuel cells.

"High power electronic inverter circuits are needed for power modules, photovoltaics, wind power, EVs and so on, and the temperature ranges for each technology may be different," Troiler-McKinstry said.

Ceramics1 

The main components of Li-ion batteries are the anode, cathode, electrolyte and separator. (Argonne National Laboratory, via Morgan Advanced Ceramics, Ceramics Expo 2016)

Ceramics in Li-ion batteries

Ceramics used in Li-ion battery separators, both in ion conducting and ion permeable applications are a growth market that many companies are not yet targeting, according to Richard Clark, strategic business development specialist for Morgan Advanced Materials.

In the year 2000, the ion permeable separator market was essentially composed of 100% polyolefin, Clark told delegates. By 2015 however, ceramic materials accounted for 44% of the market by area.

"This shift is mainly based on a drive for safety and market changes in product type and cell size," Clark said.

The main components of Li-ion batteries are comprised of the anode, cathode, electrolyte and separator. The separator has three main jobs; it serves as a barrier to electrodes, a window to ions and a reservoir for the electrolyte.

Ideally, the separator would take up as little space as possible, take up minimal space and cost less.

"Separators also play a key role in battery performance and safety, and a ceramic coating on the separator can help to address some of the safety issues faced by Li-ion batteries," Clark said.

"Currently the market is worth around $500m right now and is heading towards becoming a billion dollar market for ceramics," he added.

As a result, the last five years have seen an increase in activity in the sector, with current patent activity in the Li-ion separator sector "than ever before".

"There are a lot of different combinations of material, if you start combining these things in a market that’s growing and provides opportunity, you’ll see a lot of very clever and innovative things happening," Clark said.

Ceramics in Li-ion battery separators 

Ceramics2 

In 2000, the ion permeable separator market was 100% polyolefin. By 2015 ceramics
accounted for 44% by area. Source: Morgan Advanced Materials 

Zirconia in electrolytes 

Meanwhile in electrolyte material, Zhien Liu, development lead for fuel cell development at LG Fuel Cell Systems, fingered stabilised zirconia as the top candidate for the job, owing to its material stability at fuel cell operating conditions.

"In all fuel cell systems we use all ceramics, there is not metallic material, which is limited due to the oxidation issue at high temperatures and also the chrome contamination issue to the cathode," Liu told attendees.

Stabilised zirconia also has advantages as an electrolyte material owing to its good long term reliability for a commercial product and the ability to select different compositions to meet conductivity requirements by application.

However, the long term stability of electrolyte material is still an issue, Liu said, and further developments are needed with challenges such as the accumulation of free MnOx in LSM-based cathodes near  the electrolyte interface during fuel cell operation, and the change in cathode microstructure after two year operation.