High‐entropy oxide: A future anode contender for lithium‐ion battery

Abstract

Revolutionary changes in energy storage technology have put forward higher requirements on next-generation anode materials for lithium-ion battery. Recently, a new class of materials with complex stoichiometric ratios, highentropy oxide (HEO), has gradually emerging into sight and embracing the prosperity. The ideal elemental adjustability and attractive synergistic effect make HEO promising to break through the integrated performance bottleneck of conventional anodes and provide new impetus for the design and development of electrochemical energy storage materials. Here, the research progress of HEO anodes is comprehensively reviewed. The driving force behind phase stability, the role of individual cations, potential mechanisms for controlling properties, as well as state-of-the-art synthetic strategies and modification approaches are critically evaluated. Finally, we envision the future prospects and related challenges in this field, which will bring some enlightening guidance and criteria for researchers to further unlock the mysteries of HEO anodes.

Insights into high-entropy material synthesis dynamics criteria based on a thermodynamic framework

“…However, the current limited understanding of the growth mechanism of HEMs hinders the clarification of the solution mechanism of HEMs. 4 Since it is difficult to explain, this problem only through thermodynamic criteria, it is analyzed here from the perspective of synthesis dynamics. The whole synthesis process can be divided into two parts, 56 ion diffusion and nucleation, in which the speed of ion diffusion determines the subsequent nucleation growth mechanism.…”

“…18 Throughout the synthesis process, thermodynamics would control the overall directions of reactions. However, drawing a complete blueprint for the synthesis of HEMs based only on such state quantities is difficult since this cannot effectively clarify the solid–solution mechanism of HEMs 4 nor predict the synthesis path of the products and their surface interface properties. Consequently, predicting the improvement of the catalytic performance of HEMs using the synthesis method is challenging.…”

“…2 Features such as the lattice distortion effect, hysteresis diffusion effect, high-entropy effect, cocktail effect, and other characteristics 3 give HEMs excellent intrinsic properties and high catalytic activities. 1,4 Hence, the current continuous development of new HEMs along with the continuous optimization of their intrinsic catalytic performance have become important topics in material science. In particular, the development of HEMs has brought new impetus to the catalytic research and development field.…”

Synergy of cations in high entropy oxide lithium ion battery anode

“…Recently, high entropy oxides (HEOs) as a novel class of multication metal oxides have attracted intensive interest for battery applications [18][19][20][21][22][23][24] . In particular, it has been reported that micrometersized HEO particles show extraordinary long-term cycling stability at high capacity without a necessity for nanostructuring when used as anode material in LIBs 20 .…”

“…The unexpected performance has been attributed to the randomly mixed five metal elements in a single-phase solid solution without chemical short-range order. This has been supposed to result in a high configurational entropy, stabilizing the crystal structure during lithium storage 18,20,23,24 . However, solely considering the entropy is insufficient to explain the reversibility of the conversion reaction and the high electron conductivity that is required for the long reaction path due to the large particle size.…”