Impact of Titanium in Nickel-rich, Cobalt-free Cathodes Decoded
Nickel-rich cathodes enable high energy density in lithium ion batteries, but they rely on the critical material cobalt to remain structurally stable. Cobalt is expensive and concentrated in only a few geographical regions. To make battery production more sustainable and reduce dependencies on critical raw materials, cobalt-free materials are therefore being intensively investigated. An international research collaboration led by MEET Battery Research Center at the University of Münster has now demonstrated that cathodes for high-performance lithium ion batteries can be produced using titanium instead of cobalt while still remaining stable over many charging cycles.
Two Mechanisms for Stable Cathodes Identified
Titanium is a highly abundant and cost-effective element. Previous studies have specifically shown that titanium can improve the stability and lifetime of cobalt-free, nickel-rich cathodes. “Based on these findings, our work reveals the atomic-scale mechanism that keeps the battery cells stable,” explains MEET researcher Dr Bixian Ying. To connect the electronic changes at the atomic level with structural changes during battery operation, the team combined experimental methods with theoretical calculations.
The researchers identified two ways in which titanium can stabilize a cobalt-free, nickel-rich cathode. First, the titanium-oxygen units act like small ‘shock absorbers’ in the crystal, accommodating structural strain during charging and discharging. Second, titanium modifies its electronic environment, making the nickel-oxygen framework less prone to distortion. As a result, battery cells containing the adapted material retained 80 percent of their capacity after 431 cycles. “Understanding the precise mechanism of titanium is a crucial step towards developing a new generation of durable, cobalt-free cathodes for lithium ion batteries,” Ying summarizes.
Entire Study Available
The detailed results have been published by the authors Dr Bixian Ying, Dr Zhenjie Teng, Dr Honghong Tian, Charlotte von Petersdorff-Campen, Rommel T. Tolla, Linus Voigt, Dr Sascha Nowak, Verena Naber and Dr Karin Kleiner (MEET Battery Research Center), Dr Jun Wang (Southern University of Science and Technology, China), Dr Iuliia Mikulska (Diamond Light Source Ltd, United Kingdom), Alexander Schökel (German Electron Synchrotron DESY), Dr Yuanming Liu (Tsinghua University, China), Dr Michael Merz, Dr Peter Nagel and Dr Stefan Schuppler (Karlsruhe Institute of Technology, Germany), Katja Frenzel, Dr Adrian Jonas and Dr Lena Mathies (National Metrology Institute of Germany PTB), as well as Prof. Dr Martin Winter (MEET Battery Research Center and Helmholtz Institute Münster of Forschungszentrum Jülich), in the journal “Advanced Science”.