Mixed-Metal–Organic Framework with Effective Lewis Acidic Sites for Sulfur Confinement in High-Performance Lithium–Sulfur Batteries

Abstract

The mixed-metal-organic framework approach and a representative zirconium-metalloporphyrin framework (MOF-525) have been developed to create novel sulfur hosts and Li-S batteries. The different local environments at the centers of the porphyrin moieties in a series of MMOFs-MOF-525(2H), MOF-525(FeCl), and MOF-525(Cu)-have led to their different behaviors for the confinement of sulfur and thus Li-S batteries. The unique structure of MOF-525(Cu) has enabled each Cu(2+) site to offer two Lewis acidic sites, featuring it as a very powerful MOF host for the inclusion of sulfur and polysulfides. The S@MOF-525(Cu) cathode has demonstrated the best performance among all reported sulfur/MOFs composite cathode materials, with a reversible capacity of about 700 mAh/g at 0.5 C after 200 cycles.

Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium–sulfur batteries

“…To the best of our knowledge, the cycling and rate performance of S@ HKUST-1/CNT electrode is the best performance among MOFs-based sulfur electrodes13141516171819 (Fig. 3e, Supplementary Table 1) and competitive to those of representative high-performance carbon-based sulfur electrodes5910111234353637383940414243444546474849505152535455 (Supplementary Table 2).…”

“…Various strategies have been developed to improve the performance of Li–S batteries9101112, yet the obtained volumetric energies are still low. Recently, metal-organic frameworks (MOFs) materials with abundant porosity, high specific surface area and strong chemical bondage with sulfur species revealed a great potential in tackling the polysulfide shuttle problem and enhancing electrochemical performance of Li–S batteries13141516171819. However, several challenges, for example, the electronic insulation (generally lower than 10 −10  S cm −1 ) and the brittleness of the MOFs materials, seriously constrain the kinetics of sulfur electrochemistry and mechanical stability of the electrode, leading to poor flexibility and cell performance which should be well addressed before the employment of MOFs for flexible Li–S batteries20.…”

Novel Non‐Carbon Sulfur Hosts Based on Strong Chemisorption for Lithium–Sulfur Batteries

“…And the oxygen rich surface groups can provide additional binding via strong chemisorption. These unique structural and functional characteristics make MOFs very suitable as effective hosts to entrap sulfur for Li–S batteries . Considering Li–S batteries, sulfur cathode differs from the conventional LiCoO 2 cathode which depends on an intercalation reaction and has a stable host structure, contributing to the easy transport of both Li + and electrons, while sulfur works as a conversion cathode, where there is no steady host to confine polysulfide in the framework.…”

“…These unique structural and functional characteristics make MOFs very suitable as effective hosts to entrap sulfur for Li-S batteries. [123][124][125][126][127] Considering Li-S batteries, sulfur cathode differs from the conventional LiCoO 2 cathode which depends on an intercalation reaction and has a stable host structure, contributing to the easy transport of both Li + and electrons, while sulfur works as a conversion cathode, where there is no steady host to confine polysulfide in the framework. Therefore, it is necessary to find an additional polysulfide reservoir, [127] for this purpose, MOFs with high porosity and large surface area represent a feasible candidate.…”

Few‐Layer Boron Nitride with Engineered Nitrogen Vacancies for Promoting Conversion of Polysulfide as a Cathode Matrix for Lithium–Sulfur Batteries

“…Inspired by the pioneering work of the Manthiram group, various new types of materials combining physical adsorption and chemical bonding effects have attracted much attention owing to their strong anchoring effect on the LiPS species, such as electronegative heteroatom‐doped carbonaceous materials, metal–organic frameworks (MOFs), and transition metal sulfides, oxides, and nitrides . For F‐, S‐, and N‐doped carbonaceous materials, there are too few functional groups on the surface of the substrates to capture the LiPS species, although the heteroatoms can increase the electronegativity of the substrate surface .…”