The progress and promise for metal-organic framework-mediated synthesis of lithium-ion battery cathode materials

Research teams from Zhaoqing University and South China Normal University have provided an overview of the development of metal-organic framework (MOF)-derived lithium-ion battery (LIB) cathode materials. By the use of the MOF-mediated approach, the multiscale design of LIB cathodes from morphology, composition, and atomic/electronic configuration can be realized, resulting in a significant enhancement in lithium storage. This review provides valuable insights into the directional design of next-generation LIB cathodes.

LIBs have occupied a predominant position in the energy industry due to their considerable energy density, excellent cycle life, and environmental friendliness. Although LIBs have become prevailing electric power sources for electrical vehicles and portable devices, there remains sufficient space for the improvement of energy/power density and volumetric/mass capacity. To attain the above target, the LIB cathode technology plays an important part, which can determine the cutoff voltage and overall capacity of LIB full cells. Considering the significance and limitations of commercial cathode materials, the controllable design of LIB cathodes is necessary. The controllability and designability of MOFs render them suitable self-sacrificial templates for cathode material design.

Cathode materials with different chemical compositions and crystal structures show various Li⁺ insertion/extraction kinetics, thus affecting the electrochemical behaviors of LIBs and directly determining the energy density, power density, cycle stability, and safety performance. According to the demerits of different cathode materials (layered, spinel, and olivine structures), researchers proposed some viable solutions such as (i) nanoengineering for shortening the ion/charge diffusion pathway and easing mechanical stress, (ii) combination with conductive matrices/substrates for enhanced electrical conductivity, (iii) cation doping for mitigating the detrimental phase transformation, (iv) oxygen vacancy engineering for boosted electronic/ion conductivity and ameliorated crystallization orientation, and (v) compositional optimization for better synergism toward elevated lithium storage capacities. The MOF-mediated synthetic route can effectively integrate all the above modification methodologies, showing intriguing advantages including (i) the retention of porous structures promotes electrolyte penetration and lithium ion transport, which can expedite lithium storage kinetics; (ii) the large specific surface area of MOFs can improve the electrode/electrolyte contact area and provide more electrochemical active sites; (iii) designable compositions that enable the combination of various components for better synergism; (iv) morphological optimization that shortens the ion/charge diffusion pathways and reduces adverse side reactions; as well as (v) the construction of defects/conductive networks to boost the ion/electronic conductivity.

The MOF-mediated synthetic strategy enables precise control of targeted cathode materials, during which multilevel modification (i.e., morphology modulation, defect engineering, and carbon modification) can be realized, thereby effectively reconciling the inherent demerits of various LIB cathodes. Hence, the MOF-mediated synthetic route, as an emerging protocol, offers a blueprint for the directional design of LIB cathode materials. Nevertheless, some challenges and technical bottlenecks related to the expected cost, environmental impact, and reproducibility still thwart the mass production and industrialization of MOF-derived cathode materials. To ensure the practicability of the MOF-mediated synthetic route, some issues should be taken into account in future research, such as synthetic route optimization, systematic mechanism study, theoretical investigation, and industrial convection.

This review offers a promising pathway to realizing the directional design and modification of LIB cathodes and proposes some viable research directions for LIB technology innovation.
The review has been recently published in the online edition of Materials Futures, a prominent international journal in the field of interdisciplinary materials science research.

Reference:Lianfen Chen, Jiafan Fang, Jiexun Lin, Minying Zhao, Yiqing Liu, Jian-En Zhou, Yongbo Wu, Xiaoming Lin. The progress and promise for metal-organic framework-mediated synthesis of lithium-ion battery cathode materials[J]. Materials Futures. DOI: 10.1088/2752-5724/ade9e3

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