Engineering MOFs‐Derived Nanoarchitectures with Efficient Polysulfides Catalytic Sites for Advanced Li–S Batteries

Abstract

Owing to the dramatic growth in energy expending and the inevitable greenhouse effect, [1] it is a significant challenge to exploit new energy-storage technologies with extraordinary energy density and good sustainability. During the last decades, Li-ion batteries have played an imperative character in meeting the growing demands of electronic devices. However, as a rechargeable storage device, the Li-ion batteries have also faced many limitations because of their relatively low capacity and insufficient energy density. [2] Remarkably, lithium-sulfur batteries (LSBs) with a theoretical specific energy density of 2600 Wh kg −1 have emerged as gifted candidates to succeed Li-ion batteries, which hold quintuple theoretical gravimetric energy density compared with the presently accessible Li-ion batteries with about 400 Wh kg −1 as shown in Scheme 1A. [3][4][5][6][7][8][9] Besides, as the cathode material, sulfur is reserve-rich, inexpensive, and environmentally benign. [10,11] Compared with conventional Li-ion batteries, LSBs presented a multiple-electron conversion reaction as (S 8 →Li 2 S 8 /Li 2 S 6 →Li 2 S 4 →Li 2 S 2 /Li 2 S). The long-chain lithium polysulfide (LiPS) intermediates can dissolve into the electrolyte, but the solid LiPS intermediates (Li 2 S 2 , Li 2 S) cannot (Scheme 1B). [12][13][14][15][16][17] Generally, some persistent issues also hinder the commercial application of LSBs, including, i) during the charge and the discharge processes, the vast volume transformation (80%) of cathode should be primarily attributed to the different densities between sulfur (2.07 g cm −3 ) and Li 2 S (1.66 g cm −3 ), ii) the shuttle effect of LiPS, iii) the inefficient utilization of sulfur because of the insulation of sulfur species. [18][19][20][21][22][23] Most importantly, the sluggish conversion kinetics during the interphase of electrolyte dissolved Li 2 S x and insoluble Li 2 S 2 /Li 2 S presents a vast challenge to realizing high-performance LSBs. [24][25][26][27][28][29] In order to address the above issues, [30][31][32][33] abundant research has been devoted to carbon materials, [34][35][36][37] conductive polymers, [38][39][40] and transition metal composites. [41][42][43][44][45] However, most of these sulfur host materials cannot wholly settle the Lithium-sulfur batteries (LSBs) have received dramatically increased attention because of their manifest advantages. Nevertheless, due to the severe shuttling of lithium polysulfides (LiPSs), sluggish reaction kinetics, and the insulation of sulfur species, the practical application of LSBs is far away. To overcome the abovementioned issues, metal-organic frameworks (MOFs)-derived nanoarchitectures have emerged as one of the most promising cathode materials in designing advanced Li-S batteries. This timely progress report highlights and comments on the most recent advances in designing MOFs-derived nanoarchitectures with diverse electrocatalytic centers as cathode materials for catalyzing the oxidation/ reduction reactions of LiPS in LSBs. The molecular/atom...

Single-atom cobalt encapsulated in carbon nanotubes as an effective catalyst for enhancing sulfur conversion in lithium–sulfur batteries

“…The CoSAC@CNTs present a notable surface area (S BET ) of 920.15 m 2 g −1 , surpassing the reported values of other Co-containing catalysts from previous studies. 58,59 As per computations based on the density functional theory (DFT) methodology, the material has an average pore size of 9.7 nm and an overall pore volume of 1.4 cm 3 g −1 . The process of pyrolysis plays a role in controlling the specific surface area and porosity of substances.…”

Selective Reduction of Multivariate Metal–Organic Frameworks for Advanced Electrocatalytic Cathodes in High Areal Capacity and Long-Life Lithium–Sulfur Batteries

“…Pristine MOFs used as electrodes in batteries have been mainly restricted by their stability issues, low capacity, poor conductivity, and weak adhesion to the substrate. On the other hand, functional MOF derivatives such as metal sulfides, metal phosphide, metal oxides, and nanometals embedded in porous carbons are generally more efficient for rechargeable batteries. − The unique structural features of MOFs and their ability to coordinate different metal ions in their secondary building units as in the case of multivariate-MOFs (MTV-MOFs), makes MOFs uniquely suited for advancing the design and performance of electrocatalytic electrodes . This top-down approach enables rapid cathode fabrication and eliminates several challenges encountered with traditional methods like wet chemical methods of coprecipitation and impregnation or gas phase processes, including chemical vapor deposition and atomic layer deposition that suffer from metal nanoparticle agglomeration or the need for advanced fabrication tools. , To this end, we envisioned that thermolysis of MTV-MOFs of selected metal composition under controlled reaction conditions could lead to superior sulfur cathodes that combine a high LiPS anchoring ability and rapid redox kinetics.…”

Molecular Copper Phthalocyanine and FeOOH Modified BiVO4 Photoanodes for Enhanced Photoelectrochemical Water Oxidation

“…Based on the above modification strategies, inorganic catalysts have been widely applied to overcome intrinsic shortcomings of BiVO 4 . On this occasion, novel molecular catalysts and metal-organic framework co-catalysts, including Co-based POM (polyoxometalate), [29] porphyrin derivatives, [30] NiFe-MOFs and MIL-101, [31][32][33][34][35] and COFs, [36] have been considered as the most promising materials owing to their high catalytic activity and easy preparation.In simulation of the conversion process between solar energy and electron in photosynthesis, it is found that semiconductors in the photoelectrochemical reaction are equivalent to the role of chlorophyll to absorb sunlight through the charge transfer process, which can break the OH bond to achieve water splitting. In this case, it is found that porphyrins and phthalocyanines have similar structures to that of photosensitive chlorophyll in nature, [30,37] which are usually used as photocatalysts to increase the efficiency of photo-generated holes reaching the surface of catalyst.…”

“…Based on the above modification strategies, inorganic catalysts have been widely applied to overcome intrinsic shortcomings of BiVO 4 . On this occasion, novel molecular catalysts and metal-organic framework co-catalysts, including Co-based POM (polyoxometalate), [29] porphyrin derivatives, [30] NiFe-MOFs and MIL-101, [31][32][33][34][35] and COFs, [36] have been considered as the most promising materials owing to their high catalytic activity and easy preparation.…”