Confined Pyrolysis of ZIF‐8 Polyhedrons Wrapped with Graphene Oxide Nanosheets to Prepare 3D Porous Carbon Heterostructures

Ding, Bing; Fan, Zengjie; Lin, Qingyang; Wang, Jie; Chang, Zhi; Li, Tao; Henzie, Joel; Kim, Jeonghun; Dou, Hui; Zhang, Xiaogang; Yamauchi, Yusuke

doi:10.1002/smtd.201900277

Cited by 33 publications

(28 citation statements)

References 60 publications

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“…Other polar materials such as covalent organic framework (COF), [71] MOF, [72] zeolitic imidazolate framework (ZIF), [73] MXene, [74] and inorganic-organic composite [75] are also used to prevent the dissociation of the LiPSs in high-loading Li-S batteries. For instance, a conductive MOF membrane was grown onto the commercial separator at the liquid-solid interface (Figure 4a,b).…”

Section: Polar-polar Interactionsmentioning

confidence: 99%

Strategies toward High‐Loading Lithium–Sulfur Battery

Chen

Lei

et al. 2020

Advanced Energy Materials

310

176

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despite all these promises, three intrinsic drawbacks need to be resolved before fulfilling the promise of the market potential.First, the most stable but electronically insulating S 8 (≈10 −14 S cm −2 ) with cyclic configuration is used as the starting material in Li-S cathode, significantly limiting the full utilization of the active materials to reach the theoretical capacity. Therefore, it is the first priority to design the cathode that ensures the maximum usage of the starting materials, which sets the upper limit of the capacity performance. Second, the muti-step reduction process releases highly soluble lithium polysulfides (LiPSs) intermediates (Li 2 S x , where x = 4-8) into the organic electrolyte. [6] Unlike the batteries based on ion-insertion mechanism, [7,8] Li-S battery possesses unique and complex electrochemical/chemical processes during operation. During galvanostatic discharge process, two distinct plateaus can be verified at about 2.4 and 2.1 V in the voltage profile, corresponding to the reduction of sulfur into long-chain polysulfides and subsequent reaction from short-chain polysulfides to Li 2 S, respectively. [9] Further investigations about the reaction mechanism of Li-S battery based on experimental and theoretical studies reveal that the existence of various intermediates during electrochemical processes, indicating much more complex battery chemistry compared to the simple stepwise reaction model. [10,11] As a result, the soluble intermediates can diffuse through the polymeric separator to the anode surface, causing the loss of active materials and degradation of anode. Third, the density difference between the starting material (sulfur, 2.07 g cm −3 ) and discharge product (Li 2 S, 1.66 g cm −3 ) causes significant volumetric change during continuous cycling, damaging the integrity of the cathode structure and leading to serious capacity fading. [12] Besides above problems concerning the cathode side of the Li-S battery, other issues arose on the anode side, such as the unstable solid-electrolyte interphase (SEI), surface passivation, and uncontrolled lithium dendrite growth. [13][14][15] Stemmed from the basic problems mentioned above from the very beginning of the designed Li-S battery systems, various derivative problems were gradually unraveled during persistent efforts for improving the battery performance to approach the ultimate goal for commercialization. In the past decade, fundamental studies about Li-S battery were carried in laboratories all over the world, and it gradually put the puzzle together while brought promising performance improvement. [11,[16][17][18][19][20] However, to date, most of the lab-scale progresses have been based on batteries with sulfur loading lower than 2 mg cm −2 , Lithium-sulfur (Li-S) batteries, due to the high theoretical energy density, are regarded as one of the most promising candidates for breaking the limitations of energy-storage system based on Li-ion batteries. Tremendous efforts have been made to meet the challenge of high-performan...

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Section: Polar-polar Interactionsmentioning

confidence: 99%

Strategies toward High‐Loading Lithium–Sulfur Battery

Chen

Lei

et al. 2020

Advanced Energy Materials

310

176

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“…Yamauchi's group reported a 2D heterostructural carbon nanosheets assembled 3D porous carbon framework (PCF), which is obtained by confined pyrolysis of GO‐wrapped ZIF‐8 composites (ZIF‐8@GO) ( Figure a). [ 161 ] Electrostatic self‐assembly of the positively charged ZIF‐8 polyhedron and negatively charged GO yields ZIF‐8@GO composites, which is further converted into a continuous 3D PCF composed of polyhedron‐shaped hollow carbon coated with reduced GO (RGO) by pyrolysis (Figure 17b). We proposed here that the ultrathin GO layer doesn't seem rigid enough to induce the outward contraction of ZIF‐8 nanopolyhedrons during the pyrolysis process.…”

Section: Hollowing Mechanisms For Zif‐8/67 Derived Hcasmentioning

confidence: 99%

Section: Hollowing Mechanisms For Zif‐8/67 Derived Hcasmentioning

confidence: 99%

Hollow Carbon‐Based Nanoarchitectures Based on ZIF: Inward/Outward Contraction Mechanism and Beyond

Song

Jiang

Cheng

et al. 2020

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Hollow carbon‐based nanoarchitectures (HCAs) derived from zeolitic imidazolate frameworks (ZIFs), by virtue of their controllable morphology and dimension, high specific surface area and nitrogen content, richness of metal/metal compounds active sites, and hierarchical pore structure and easy exposure of active sites, have attracted great interests in many fields of applications, especially in heterogeneous catalysis, and electrochemical energy storage and conversion. Despite various approaches that have been developed to prepare ZIF‐derived HCAs, the hollowing mechanism has not been clearly disclosed. Herein, a specialized overview of the recent progress of ZIF‐derived HCAs is introduced to provide an insight into their preparation strategy and the corresponding hollowing mechanisms. Based on the fundamental understanding of the structural evolution of ZIF nanocrystals during the high‐temperature pyrolysis process, the hollowing mechanisms of ZIF‐derived HCAs are classified into four categories: i) inward contraction of core–shell template@ZIF composites or hollow ZIFs, ii) outward contraction of ZIF@shell composites, iii) special outward contraction of ZIF arrays, and iv) mechanism beyond inward/outward contraction of pure ZIF nanocrystals. Finally, an outlook on the development prospects and challenges of HCAs based on ZIF precursors, especially in terms of controlled synthesis and future electrochemical application, is further discussed.

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“…[116][117][118] Consequently, various MOF/graphenederived carbonaceous materials have been fabricated and show great potential in the eld of energy storage and conversion. [119][120][121] Among them, zeolitic imidazolate frameworks (ZIFs)/ graphene-derived carbonaceous materials are intensively investigated, mainly due to the large surface area and effective nitrogen doping caused by the methylimidazole (MeIM) ligand, which are benecial for the improved electrical conductivity, catalytic activity, capacitive performance, etc. 61 Zhang's group prepared graphene-based nitrogen-doped porous carbon sheets (GNPCSs) upon direct pyrolysis of the 2D sandwich-like GO/ZIF-8 composite and subsequent etching of the possible residual Zn species with acid (Fig.…”

Section: Design and Preparation Of Mof/graphene-derived Carbonaceous Materialsmentioning

confidence: 99%

“…Ding et al developed a facile method to fabricate a 3D porous carbon framework (PCF) constructed from 2D heterostructured carbon nanosheets. 121 As shown in Fig. 5g , the hybrid GO/ZIF-8 composite was easily prepared by vacuum filtration of a GO coated ZIF-8 composite, which was formed through electrostatic self-assembly of negatively charged GO nanosheets and positively charged ZIF-8 polyhedra.…”

Section: Introductionmentioning

confidence: 99%