Photonic Surface Coating of Compositionally Complex Oxides for Battery Applications

Heightened attention has been directed towards compositionally complex materials (CCM), including high entropy materials, owing to their distinct properties as potential battery cell components.^[1] Lithium-doped high-entropy oxides (LiHEOs) exemplified by Li_0.33(MgCoNiCuZn)_0.67O exhibit notable lithium ion and electron conductivity.^[2,3] This renders them promising as coating materials for NCM (Lithium-Nickel-Cobalt-Manganese Oxide) in conventional Li-ion battery (LIBs) cells, due to their high ionic and electronic conductivity. However, the stringent conditions and high temperatures required for their synthesis impose limitations on their practical application.
To overcome these challenges, a novel photonic curing strategy is introduced for the synthesis of compositionally complex materials. This approach successfully yields, for the first time, a nanoscale, homogeneous coating layer on NCM particles.^[4,5] The modified surface of NCM with the CCM demonstrates exceptional electrochemical cycling stability, exhibiting a noteworthy 91% capacity retention at 1C after 200 cycles. This enhanced electrochemical performance can be attributed to the uniform coating, which effectively mitigates structural changes resulting from the interaction between the electrode active material and electrolyte.
In comparison to the uncoated NCM, the presence of a coating substantially reduces the formation of cracks in secondary particles. This reduction in crack formation prevents the electrolyte from further reacting with primary particles along the cracks. The findings suggest the potential of CCM-modified materials as a viable solution for improving the electrochemical performance and cycling stability of high nickel cathode active materials and thereby increasing the cycle life of LIBs. Further, photonic curing presents a novel synthesis and coating procedure for cathode active material particles that paves the way for surface modification of any heat sensitive material for a number of applications using a cost and energy efficient approach.
[1] Y. Ma, Y. Ma, Q. Wang, S. Schweidler, M. Botros, T. Fu, H. Hahn, T. Brezesinski, B. Breitung, Energy Environ. Sci. 2021, 14, 2883.
[2] D. Berardan, S. Franger, A. K. Meena, N. Dragoe, J. Mater. Chem. A 2016, 4, 9536.
[3] M. Mozdzierz, J. Dabrowa, A. Stepien, M. Zajusz, M. Stygar, W. Zajac, M. Danielewski, K. Swierczek, Acta Mater. 2021, 208.
[4] H. Sommer, X. Wu, M. Botros, B. Breitung, S. Schweidler, T. Brezesinski, H. Hahn, Process of Making a Coated Cathode Active Material, and Coated Active Material, 2023.
[5] Y. Cui, Y. Tang, J. Lin, J. Wang, H. Hahn, B. Breitung, S. Schweidler, T. Brezesinski, M. Botros, Small Structures. 2024, 2400197.