Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electrode materials from the microwave oven

19.10.2017

Novel process facilitates production of high-voltage cathodes for lithium-ion batteries

Power on the go is in demand: The higher the battery capacity, the larger the range of electric cars and the longer the operating time of cell phones and laptops. Dr. Jennifer Ludwig of the Technical University of Munich (TUM) has developed a process that allows a fast, simple, and cost-effective production of the promising cathode material lithium cobalt phosphate in high quality. The chemist was awarded the Evonik Research Prize for her work.


Dr. Jennifer Ludwig at the Technical University of Munich (TUM) has developed a process, that allows a fast, simple, and cost-effective production of nanocrystalline lithium cobalt phosphate crystals. Compared to standard lithium iron phosphate this material improves the energy density of lithium-ion batteries from about 600 to 800 watt hours per kilogram.

Credit: Andreas Battenberg / TUM

Hope is pink: The powder that Jennifer Ludwig carefully pours into a glass bowl and which glows pink in the light of the laboratory lamp has the potential to significantly improve the performance of future batteries. "Lithium cobalt phosphate can store substantially more energy than conventional cathode materials," explains the chemist.

Working in the group of Tom Nilges, head of the Professorship of Synthesis and Characterization of Innovative Materials, the chemist has developed a process for producing the pink powder quickly, with minimal amounts of energy and in the highest quality.

Battery researchers have been considering lithium cobalt phosphate a material of the future for some time. It operates at higher voltages than the traditionally employed lithium iron phosphate and thus, attains a higher energy density - 800 watt hours per kilogram instead of just under 600 watt hours.

Previous process: expensive and energy-intensive

Previously, however, the production of the promising high-voltage cathode material required a very complex, energy-intensive and inefficient process under harsh conditions with temperatures of 800 °C. "And the crystals that form under these conditions vary in size and must be ground to nanocrystalline powder in a second, energy-intensive production step," reports Ludwig.

Furthermore, the resulting crystals exhibit sufficient ionic conductivity in only one direction. Over most of the surface, the chemical reaction between the electrode material and the electrolyte in the batteries progresses very slowly.

Tailored crystals

The microwave synthesis process developed by Jennifer Ludwig solves all of these issues at once: Obtaining the high-grade lithium cobalt phosphate requires only a microwave oven and 30 minutes of time.

The reactants are placed in a Teflon container together with a solvent and are then heated. A mere 600 W are sufficient to achieve the 250 °C required to stimulate the crystal formation.

The flat platelets created in the process measure less than one micrometer across and are only a few hundred nanometers thick, with the axis of maximum conductivity oriented towards the surface. "This shape ensures better electrochemical performance because the lithium ions need to move only short distances within the crystals," explains Ludwig.

Steering the reaction

The chemist was also able to solve another problem in the course of her experiments: At temperatures over 200 °C and under high pressure, instead of the desired lithium cobalt phosphate a hitherto unknown, complex cobalt hydroxide hydrogen phosphate compound is occasionally formed.

Jennifer Ludwig succeeded in elucidating the reaction mechanism, isolating the compound and determining its structure and properties. Since the new compound is unsuitable as a battery material, she modified the reaction so that only the desired lithium cobalt phosphate is produced.

"With this new production process, we can now create high-performance, platelet-shaped lithium cobalt phosphate crystals with tailored properties in high quality," says Professor Nilges. "Thus, a further hurdle on the path to new high-voltage materials has been taken."

###

Jennifer Ludwig's work was funded by the TUM Graduate School, BMW, and the Chemical Industry Fund. The investigation of electrochemical properties was performed in cooperation with the Chair of Technical Electrochemistry, TU Munich. The structure and properties of the complex cobalt hydroxide hydrogen phosphate were investigated in collaboration with the Lawrence Berkeley National Laboratory (LBNL), the Stanford Synchrotron Radiation Light Source (SSRL) and the Walther-Meißner-Institut (WMI). For the development of the new synthesis process, Jennifer Ludwig received the Evonik Research Prize, which the chemical company annually awards to next-generation researchers.

Media Contact

Dr. Andreas Battenberg
battenberg@zv.tum.de
49-892-891-0510

 @TU_Muenchen

http://www.tum.de 

Dr. Andreas Battenberg | EurekAlert!

More articles from Materials Sciences:

nachricht Mat4Rail: EU Research Project on the Railway of the Future
23.02.2018 | Universität Bremen

nachricht Atomic structure of ultrasound material not what anyone expected
21.02.2018 | North Carolina State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>