Ionic Liquid@Metal-Organic Framework as a Solid Electrolyte in a Lithium-Ion Battery: Current Performance and Perspective at Molecular Level

MOF-modified dendrite-free gel polymer electrolyte for zinc-ion batteries

Zinc-ion batteries are promising candidates for large-scale energy storage, and gel polymer electrolytes (GPEs) play an important role in zinc-ion battery applications. Metal-organic frameworks (MOFs) are characterized by large specific surface areas and ordered pores. This highly ordered microporous structure provides a continuous transport channel for ions, thus realizing the high-speed transmission of ions. In this paper, an MOF-modified dendrite-free GPE was designed. The incorporation of MOF particles not only reduces the crystallinity of the polymer, increases the motility of the molecular chains, and facilitates the transfer of Zn2+, but also attracts anions to reduce polarization during electrochemical reactions. It was shown that this MOF-modified gel polymer electrolyte has a higher ionic conductivity compared to other PVDF-based polymer electrolytes (approximate range of 2 × 10-4 to 3 × 10-3 S cm-1), with a very high conductivity (1.63 mS cm-1) even at -20 °C. The Zn/Zn symmetric cell could maintain operation for more than 3600 h at a current density of 1 mA cm-2, and SEM showed that the MOF-modified gel electrolyte had uniform Zn2+ deposition.

Electrochemical coupling in subnanometer pores/channels for rechargeable batteries

Subnanometer pores/channels (SNPCs) play crucial roles in regulating electrochemical redox reactions for rechargeable batteries. The delicately designed and tailored porous structure of SNPCs not only provides ample space for ion storage but also facilitates efficient ion diffusion within the electrodes in batteries, which can greatly improve the electrochemical performance. However, due to current technological limitations, it is challenging to synthesize and control the quality, storage, and transport of nanopores at the subnanometer scale, as well as to understand the relationship between SNPCs and performances. In this review, we systematically classify and summarize materials with SNPCs from a structural perspective, dividing them into one-dimensional (1D) SNPCs, two-dimensional (2D) SNPCs, and three-dimensional (3D) SNPCs. We also unveil the unique physicochemical properties of SNPCs and analyse electrochemical couplings in SNPCs for rechargeable batteries, including cathodes, anodes, electrolytes, and functional materials. Finally, we discuss the challenges that SNPCs may face in electrochemical reactions in batteries and propose future research directions.

A mini review of current studies on metal-organic frameworks-incorporated composite solid polymer electrolytes in all-solid-state lithium batteries

All-solid-state lithium batteries (ASSLBs) using solid polymer electrolytes (SPEs) are believed to be future next-generation batteries aiming to replace high-risk traditional batteries using liquid electrolytes, which have a wide application range in portable electronic devices, portable power supplies, and especially in electric vehicles. Moreover, the appearance of SPEs can overcome the electrolyte leakage and flammability problems in conventional lithium-ion batteries. Nevertheless, ASSLBs still face some limitations due to the low ionic conductivity of solid-state electrolytes (SSEs) at room temperature and the poor contact electrode/electrolyte interface, which can be solved by suitable strategies. Currently, the research strategies of metal-organic frameworks that can be incorporated into solid polymer electrolytes offer a remarkable method for producing uniform solid polymer electrolytes that have good electrode/electrolyte contact interfaces and high ionic conductivity. Herein, the updates of current studies about metal-organic framework-incorporated composite solid polymer electrolytes are discussed in this mini-review.

Exploring ionic liquid-laden metal-organic framework composite materials as hybrid electrolytes in metal (ion) batteries

This review focuses on the combination of metal-organic frameworks (MOFs) and ionic liquids (ILs) to obtain composite materials to be used as solid electrolytes in metal-ion battery applications. Benefiting from the controllable chemical composition, tunable pore structure and surface functionality, MOFs offer great opportunities for synthesizing high-performance electrolytes. Moreover, the encapsulation of ILs into porous materials can provide environmentally benign solid-state electrolytes for electrochemical devices. Due to the versatility of MOF-based materials, in this review we also explore their use as anodes and cathodes in Li- and Na-ion batteries. Finally, solid IL@MOF electrolytes and their implementation into Li and Na batteries have been analyzed, as well as the design and advanced manufacturing of solid IL@MOF electrolytes embedded on polymeric matrices.