Modulating Metal–Organic Frameworks as Advanced Oxygen Electrocatalysts

Li, Zhaoqiang; Gao, Rui; Feng, Ming; Deng, Yaping; Xiao, Dingfu; Zheng, Yun; Zhao, Zhao; Luo, Dan; Liu, Youlin; Zhang, Zhen; Wang, Dandan; Li, Qian; Li, Haibo; Wang, Xin; Chen, Zhongwei

doi:10.1002/aenm.202003291

Cited by 118 publications

(83 citation statements)

References 204 publications

(199 reference statements)

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“…Metal–organic frameworks (MOFs), as an emerging versatile platform with metal nodes bonded with organic ligands, [18–20] are effective electrocatalysts for aprotic Li−O 2 batteries, which can simultaneously afford high discharge capacity and moderate charge kinetics [21–23] . However, the bulk MOF cathodes suffer from inferior conductivity and blockage of active metal sites by guest ligands, resulting in a large voltage hysteresis of over 1.5 V. Rational design and synthesis of two/one‐dimensional conductive MOFs enables facile electron transfer, exposure of active surfaces, and unsaturated metal centers, which promise to raise the number of active sites to enhance the electrocatalytic activity [24–28] .…”

Section: Introductionmentioning

confidence: 99%

Spin‐State Manipulation of Two‐Dimensional Metal–Organic Framework with Enhanced Metal–Oxygen Covalency for Lithium‐Oxygen Batteries

Zhu

et al. 2022

Angew Chem Int Ed

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Aprotic Li−O2 batteries have attracted extensive attention in the past decade owing to their high theoretical energy density; however, they are obstructed by the sluggish reaction kinetics at the cathode and large voltage hysteresis. We regulate the spin state of partial Ni2+ metal centers (t2g6eg2) of conductive nickel catecholate framework (NiII‐NCF) nanowire arrays to high‐valence Ni3+ (t2g6eg1) for NiIII‐NCF. The spin‐state modulation enables enhanced nickel–oxygen covalency in NiIII‐NCF, which facilitates electron exchange between the Ni sites and oxygen adsorbates and accelerates the oxygen redox kinetics. Upon discharging, the high affinity of Ni3+ sites with the intermediate LiO2 promotes formation of nanosheet‐like Li2O2 in the void space among NiIII‐NCF nanowires. The Li−O2 battery based on NiIII‐NCF offers remarkably reduced discharge/charge voltage gaps, superior rate capability, and a long cycling stability of over 200 cycles. This work highlights the importance of electron spin state on the redox kinetics and will provide insight into electronic structure regulation of electrocatalysts for Li−O2 batteries and beyond.

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Section: Introductionmentioning

confidence: 99%

Spin‐State Manipulation of Two‐Dimensional Metal–Organic Framework with Enhanced Metal–Oxygen Covalency for Lithium‐Oxygen Batteries

Zhu

et al. 2022

Angew Chem Int Ed

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“…If the adsorption interaction is too strong, however, it will hinder the removal of products. [55] The tuning of intrinsic activities of electrocatalysts can be achieved by adjusting the adsorption energy of intermediates on active sites.…”

Section: Electrocatalysismentioning

confidence: 99%

Molecular Cleavage of Metal‐Organic Frameworks and Application to Energy Storage and Conversion

et al. 2021

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topology, and pore structure. This has led to research via various chemical approaches to control precisely chemical moieties within the structure of MOFs. [3] However, the direct (bottom-up) synthesis of MOFs from metal ions and ligands is not always feasible due to factors, including limited reactant concentration, lack of solvent, improper reaction temperature, and undesired side reactions. [4] Therefore, postsynthesis (top-down) methods are receiving increased research attention. This approach is seen as being flexible to modulate the structure of assynthesized MOFs. [5] For example, the synthesis of defects via missing clusters can regulate the pore volume of derived MOFs to boost CO 2 capture from flue gas. [6] Additionally, missing linkers not only create vacancy sites in MOF-808 (Zr 6 O 5 (OH) 3 (BTC) 2 (HCOO) 5 (H 2 O) 2 , BTC = 1,3,5-benzenetricarboxylate) and UiO-66 (University in Oslo, Zr 6 O 4 (OH) 4 (BDC) 6 , BDC = terephthalic acid) but introduce OH groups, which work as Brønsted bases to facilitate tertbutyl alcohol catalytic dehydration. [7] Weakening of the energy of metal-linker coordination bonds provides an opportunity to achieve postsynthesis of MOFs. [8] Using simple thermal pyrolysis, derivatives such as transitionmetal-based materials, single-atom catalysts, and carbon materials have been prepared for catalysis and energy-related applications. [9] However, the structure of MOFs is destroyed during many of these treatments. As a result, MOFs serve only as precursors for the derivatives rather than the direct active materials in catalytic application. [] Here, we focus on postsynthesis methods involving selective chemical bond cleavage to tailor composites and create new MOF structures. This method is advantageous because the reticular chemistry structure of the parent is not destroyed.Posttreatment of MOFs can be conveniently categorized as one of each of three distinct methods: 1) introduction of foreign metal ions or ligands into a pristine structure via exchange reactions; [4] 2) solvent-assisted incorporation of linkers on vacant/labile sites into the structure; [11] and 3) partial destruction to a new structure. [12] Generally, for the first two, the insertion of linkers with desired functional groups is not always trivial because these groups coordinate to metal sites during synthesis, losing functionalities. [13] The destruction of MOFs by cleavage of coordination bonds between metal and solvent molecules/linkers to precisely tune structures generates opening of metal sites, defects, hierarchical pores, orThe physicochemical properties of metal-organic frameworks (MOFs) significantly depend on composition, topology, and porosity, which can be tuned via synthesis. In addition to a classic direct synthesis, postsynthesis modulations of MOFs, including ion exchange, installation, and destruction, can significantly expand the application. Because of a limitation of the qualitative hard and soft acids and bases (HSAB) theory, posttreatment permits regulation of MOF structure by cleavi...

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“…Metal-organic frameworks (MOFs), as an emerging versatile platform with metal nodes bonded with organic ligands, [18][19][20] are effective electrocatalysts for aprotic LiÀ O 2 batteries, which can simultaneously afford high discharge capacity and moderate charge kinetics. [21][22][23] However, the bulk MOF cathodes suffer from inferior conductivity and blockage of active metal sites by guest ligands, resulting in a large voltage hysteresis of over 1.5 V. Rational design and synthesis of two/one-dimensional conductive MOFs enables facile electron transfer, exposure of active surfaces, and unsaturated metal centers, which promise to raise the number of active sites to enhance the electrocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Spin‐State Manipulation of Two‐Dimensional Metal–Organic Framework with Enhanced Metal–Oxygen Covalency for Lithium‐Oxygen Batteries

Zhu

et al. 2022

Angewandte Chemie

View full text Add to dashboard Cite

Aprotic LiÀ O 2 batteries have attracted extensive attention in the past decade owing to their high theoretical energy density; however, they are obstructed by the sluggish reaction kinetics at the cathode and large voltage hysteresis. We regulate the spin state of partial Ni 2 + metal centers (t 2g 6 e g 2 ) of conductive nickel catecholate framework (Ni II -NCF) nanowire arrays to high-valence Ni 3 + (t 2g 6 e g 1 ) for Ni III -NCF. The spin-state modulation enables enhanced nickel-oxygen covalency in Ni III -NCF, which facilitates electron exchange between the Ni sites and oxygen adsorbates and accelerates the oxygen redox kinetics. Upon discharging, the high affinity of Ni 3 + sites with the intermediate LiO 2 promotes formation of nanosheet-like Li 2 O 2 in the void space among Ni III -NCF nanowires. The LiÀ O 2 battery based on Ni III -NCF offers remarkably reduced discharge/charge voltage gaps, superior rate capability, and a long cycling stability of over 200 cycles. This work highlights the importance of electron spin state on the redox kinetics and will provide insight into electronic structure regulation of electrocatalysts for LiÀ O 2 batteries and beyond.

show abstract

Modulating Metal–Organic Frameworks as Advanced Oxygen Electrocatalysts

Cited by 118 publications

References 204 publications

Spin‐State Manipulation of Two‐Dimensional Metal–Organic Framework with Enhanced Metal–Oxygen Covalency for Lithium‐Oxygen Batteries

Spin‐State Manipulation of Two‐Dimensional Metal–Organic Framework with Enhanced Metal–Oxygen Covalency for Lithium‐Oxygen Batteries

Molecular Cleavage of Metal‐Organic Frameworks and Application to Energy Storage and Conversion

Spin‐State Manipulation of Two‐Dimensional Metal–Organic Framework with Enhanced Metal–Oxygen Covalency for Lithium‐Oxygen Batteries

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