Metallo-N-Heterocycles - A new family of hydrogen storage material

Tan, Khai Chen; Yu, Yang; Chen, Ruting; He, Teng; Jing, Zhiyou; Pei, Qijun; Wang, Jintao; Chua, Yong Shen; Wu, Anan; Zhou, Wei; Wu, Hui; Chen, Ping

doi:10.1016/j.ensm.2019.12.035

Cited by 32 publications

(22 citation statements)

References 25 publications

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“…4. The result of sodium pyrrolide is in good agreement with the previous report 18 , showing the formation of targeted product. Lithium pyrrolides, both from ball milling and wet chemical method exhibited similar diffraction patterns, which were different from pristine LiH, suggesting the formation of new phases.…”

Section: Characterizationssupporting

confidence: 92%

“…2b). However, the C atoms which close to and far from N atom showed downfield and upfield shift, respectively, agreeing well with our previous theoretical simulation 18 .…”

Section: Characterizationssupporting

confidence: 92%

“…In comparison, the absorptions of lithium pyrrolide and sodium pyrrolide demonstrated red shifts and the intensities became obviously stronger, i.e., the wavelengths at 259.0 and 259.2 nm were attributed to lithium and sodium pyrrolides, respectively, suggesting the enhancement of conjugation effect. Moreover, it was found that the conjugation effect in sodium pyrrolide is slightly stronger than lithium pyrrolide, agreeing well with our theoretical calculation results that sodium could donate more electron to pyrrole ring 18 . Therefore, the formation of alkali pyrrolides was further demonstrated.…”

Section: Characterizationssupporting

confidence: 90%

“…It was reported that cyclic organic hydrides with electron donating groups outside the carbon-rings showed lower dehydrogenation enthalpy changes 16 . Very recently, we proposed a metallation strategy, i.e., replacing the active hydrogen atom in organic hydrides by alkali or alkaline earth metals, and a series of metalorganic hydrides with superior thermodynamic properties were successfully developed [17][18][19] . For instance, the ∆Hd of Nheterocycles could be reduced efficiently by forming metallo-Nheterocycles, where the optimized thermodynamics is due to the electron donation from the metal to organic ring.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization, and Crystal Structure of Lithium Pyrrolide

Jing¹,

Tan²,

He³

et al. 2020

Acta Physico Chimica Sinica

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Development of clean energy is an urgent requirement because of the depletion of fossil energy sources and increasingly severe environmental pollution. However, the lack of safe and efficient hydrogen storage materials is one of the bottlenecks in the implementation of hydrogen energy. Liquid organic hydrogen carriers (LOHCs) have been recognized as potential materials for the storage and transportation of hydrogen owing to their high gravimetric and volumetric hydrogen densities, reversible hydrogen absorption and desorption ability, and ease of widespread implementation with minimal modification on the existing fueling infrastructure. While some LOHCs such as cycloalkanes and N-heterocycles have been developed for hydrogen storage, they require a high hydrogen release temperature due to the large enthalpy change of dehydrogenation. In our previous work, a metallation strategy was proposed to improve the thermodynamic properties of liquid organic hydrogen carriers for hydrogen storage, and a series of metalorganic hydrides were synthesized and investigated. Among them, sodium phenoxide-cyclohexanolate pair, lithium carbazolide-perhydrocarbazolide, and sodium anilinide-cyclohexylamide pair showed promising dehydrogenation thermodynamics and improved hydrogen storage properties. Sodium pyrrolide and sodium imidazolide were also synthesized. However, pyrrolides were not well characterized, and the structure of lithium pyrrolide was not resolved. In the present study, we synthesized sodium and lithium pyrrolides by ball milling and wet chemical methods. One equivalent of hydrogen could be released from the reaction of pyrrole and metal hydrides, indicating the replacement of H by metal. The formation of pyrrolides was confirmed by nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and ultravioletvisible spectroscopy analyses. The 1 H signals attributed to C-H in the NMR spectra of the alkali metal pyrrolides shifted upfield due to the replacement of the H of N-H with a stronger electron-donating species (Li or Na), resulting in a greater shielding environment upon metallation. The absorption peaks of lithium and sodium pyrrolides showed red shifts, and the intensities became obviously stronger in the UV-Vis spectra, suggesting an enhancement of the conjugation effect, in accordance with theoretical calculations. The structure of lithium pyrrolide was determined by the combined direct space method and first-principles calculations on XRD data and Rietveld refinement. This molecule crystallizes in the monoclinic P21/c (14) space group, with lattice parameters of a = 4.4364(7) Å, b = 11.969(2) Å, c = 8.192(2) Å, β = 108.789(8)°, and V = 411.8(2) Å 3 (1 Å = 0.1 nm). Each Li + cation is surrounded by three pyrrolides via cation-N σ bonding with two pyrrolides and a cation-π interaction with the third pyrrolide, where the Li + is on the top of the π face. Our experimental findings are different from the theoretical prediction in the literature.

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Section: Characterizationssupporting

confidence: 92%

“…2b). However, the C atoms which close to and far from N atom showed downfield and upfield shift, respectively, agreeing well with our previous theoretical simulation 18 .…”

Section: Characterizationssupporting

confidence: 92%

Section: Characterizationssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis, Characterization, and Crystal Structure of Lithium Pyrrolide

Jing¹,

Tan²,

He³

et al. 2020

Acta Physico Chimica Sinica

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“…Screening promising materials from a larger number of candidates via routine experimental syntheses and property evaluations is extremely inefficient. Until now, only a couple of candidates which satisfy the two aforementioned key criteria were developed, such as lithium and sodium carbazolides . Therefore, it is highly demanding to screen materials by wide-ranging theoretical prediction, aiming to guide experimental synthesis and improve efficiency.…”

mentioning

confidence: 99%

Developing Ideal Metalorganic Hydrides for Hydrogen Storage: From Theoretical Prediction to Rational Fabrication

Jing

Yuan

et al. 2021

ACS Materials Lett.

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Materials for hydrogen storage have been extensively explored for a few decades. Thousands of materials have been synthesized and tested; however, few systems could meet the practical requirements. Metalorganic hydrides discovered recently offer new opportunities. It is, however, extremely time-consuming and inefficient to experimentally screen potential materials from a large variety of metal cations and organic anions. In the present study, we performed wide-ranging theoretical predictions and screened more than 90 metalorganic hydrides; 20 of them were identified with both high hydrogen capacities (≥5 wt %) and suitable thermodynamics (heat of H2 desorption: 25–35 kJ/mol-H2) that allow hydrogen uptake and release near ambient condition. We picked up four of them, i.e., Li/Na indolides and 7-azaindolides, for experimental validation. All the four candidates can be easily synthesized via the reactions between the metal hydrides and the corresponding organic precursors. Among them the structures of lithium indolide (P21/c (no. 14)) and sodium 7-azaindolide (P4̅21 c (no. 114) were successfully resolved. Photoelectron spectroscopy and quantum chemical calculations confirmed that the charge density of the organic ring increased with the introduction of an alkali metal, thus optimizing their ΔH d for hydrogen storage. Importantly, we demonstrated experimentally that lithium indolide with a theoretical hydrogen capacity of 6.1 wt % has a heat of hydrogen absorption of ca. 33.7 kJ/mol-H2 which is in excellent agreement with the value (33.6 kJ/mol-H2) predicted theoretically. The partially reversible hydrogen release and uptake can be can be achieved at the temperature as low as 100 °C. These results illustrate the great potential of metalorganic hydrides for tackling the grand challenge of hydrogen storage and manifest the effectiveness of theoretical prediction in guiding materials fabrication.

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Synthesis, Structure, and Ion Conduction of Potassium Carbazolides for Potassium Ion Solid‐State Electrolytes

Guo,

Yu,

Tan

et al. 2024

Adv Funct Materials

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Potassium ion batteries gradually have aroused worldwide interest due to the limited lithium resource. However, the research on the solid‐state potassium‐ion batteries is at its very early stage. The lack of electrolytes with high ionic conductivity and interfacial stability is the major obstacle. In this work, a new phase of potassium carbazolide (KC12H8N, β‐KCZ) is synthesized and expected to be less rigid in the stacking layers than the reported α‐KCZ, indicating weaker cation−π interactions. Upon complexing KCZ with THF, a new type of potassium solid‐state electrolyte is successfully developed (KxCZ‐yTHF), particularly, an optimal composition K0.9CZ‐0.7THF reveals an ionic conductivity as high as 4.2 × 10−4 S cm−1 at 100 °C, which is among the top K+ conductors at this temperature. Furthermore, KxCZ‐yTHF also demonstrates a remarkable electrochemical stability window of 3.1 V, as well as outstanding interfacial stability and compatibility against K2S electrode during a 400‐h electrochemical cycling test. Other advantages of this electrolyte include cold pressing for molding, ease for scaling up, and high safety upon exposure to air. To the best of the knowledge, this is the first report that a potassium organic compound is employed as potassium solid‐state electrolyte.

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Metallo-N-Heterocycles - A new family of hydrogen storage material

Cited by 32 publications

References 25 publications

Synthesis, Characterization, and Crystal Structure of Lithium Pyrrolide

Synthesis, Characterization, and Crystal Structure of Lithium Pyrrolide

Developing Ideal Metalorganic Hydrides for Hydrogen Storage: From Theoretical Prediction to Rational Fabrication

Synthesis, Structure, and Ion Conduction of Potassium Carbazolides for Potassium Ion Solid‐State Electrolytes

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