Pyrrolic‐Type Nitrogen‐Doped Hierarchical Macro/Mesoporous Carbon as a Bifunctional Host for High‐Performance Thick Cathodes for Lithium‐Sulfur Batteries

Han, Pauline; Chung, Sheng Heng; Manthiram, Arumugam

doi:10.1002/smll.201900690

Cited by 43 publications

(27 citation statements)

References 54 publications

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“…Various strategies have been proposed to address the above-mentioned issues, [8,9] and high-profile breakthroughs have been achieved such as ultra-high rate performance (over 40 C), [10] excellent cycling life (over 1500 cycles), [11] and high sulfur utilization (over 90 %). [12] However, it should be noted that these results are usually evaluated under ideal conditions, especially with excessive electrolyte (electrolyte/sulfur ratio, that is, E/S ratio, is typically higher than 10 mL mg S À1 ). High E/S ratios have been demonstrated to significantly increase the discharge…”

Section: Introductionmentioning

confidence: 99%

Lithium–Sulfur Batteries under Lean Electrolyte Conditions: Challenges and Opportunities

et al. 2020

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The development of energy‐storage devices has received increasing attention as a transformative technology to realize a low‐carbon economy and sustainable energy supply. Lithium–sulfur (Li–S) batteries are considered to be one of the most promising next‐generation energy‐storage devices due to their ultrahigh energy density. Despite the extraordinary progress in the last few years, the actual energy density of Li–S batteries is still far from satisfactory to meet the demand for practical applications. Considering the sulfur electrochemistry is highly dependent on solid‐liquid‐solid multi‐phase conversion, the electrolyte amount plays a primary role in the practical performances of Li–S cells. Therefore, a lean electrolyte volume with low electrolyte/sulfur ratio is essential for practical Li–S batteries, yet under these conditions it is highly challenging to achieve acceptable electrochemical performances regarding sulfur kinetics, discharge capacity, Coulombic efficiency, and cycling stability especially for high‐sulfur‐loading cathodes. In this Review, the impact of the electrolyte/sulfur ratio on the actual energy density and the economic cost of Li–S batteries is addressed. Challenges and recent progress are presented in terms of the sulfur electrochemical processes: the dissolution–precipitation conversion and the solid–solid multi‐phasic transition. Finally, prospects of future lean‐electrolyte Li–S battery design and engineering are discussed.

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Section: Introductionmentioning

confidence: 99%

Lithium–Sulfur Batteries under Lean Electrolyte Conditions: Challenges and Opportunities

et al. 2020

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“…More importantly, the N‐HPCS/S sample also shows awe‐inspiring cycling performance at 0.1 C (Figure S10d) and 1 C (Figure 4e) rates. As shown in Figure 4e, the discharge capacity of HPCS/S at 1 C rate is 529.4 mA h g −1 at the first cycle and decreases to 162.1 mA h g −1 at the 910 th cycle (capacity decay: 0.069 % per cycle), the relatively fast decay should be ascribed to the low surface specific area, and lack of effective pore structure and chemical bonding sites [41,46,56] . On the contrary, the N‐HPCS/S sample delivers a high capacity of 1102.7 mA h g −1 at the initial cycle and an impressive capacity of 646.9 mA h g −1 at the 1000 th cycle (capacity decay: 0.041 % per cycle).…”

Section: Resultsmentioning

confidence: 95%

Sustainable Synthesis of N‐Doped Hollow Porous Carbon Spheres via a Spray‐Drying Method for Lithium‐Sulfur Storage with Ultralong Cycle Life

Liu

Guo

Zhang

et al. 2020

Batteries & Supercaps

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Exploring high‐efficiency, long‐term cycling stability, and cost‐effective cathode materials for lithium‐sulfur (Li−S) batteries is hugely desirable and challenging. Herein, we have successfully developed a simple solution‐based spray‐drying method to fabricate nitrogen‐doped hollow porous carbon spheres (N‐HPCS) with biomass lignin as a carbon precursor and cyanuric acid as a N‐dopant and a porogen. The obtained N‐HPCS shows a specific surface area of 446.2 m2 g−1 and high‐level pyrrolic‐N doping of 64.13 %. The N‐HPCS/S cathode has a high initial discharge capacity of 1535.1 and 1104.0 mA h g−1 at 0.1 and 1 C, respectively. In addition, the N‐HPCS/S electrode exhibits outstanding cycle performance after 1000 cycles at 1 C, with a low capacity decay rate of only 0.041 % per cycle, which is superior to most of the recently reported carbon‐based S cathodes. N‐doping causes strong Li2Sx−N chemical adhesion in carbon spheres, effectively suppressing the dissolution and “shuttle effect” of the notorious polysulfide of Li−S batteries, in which pyrrolic‐N plays a leading role in the capture of polysulfides intermediates. This contribution is of great significance to the exploration of many other structure‐property design strategies for ultralong cycle life Li−S energy storage devices.

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“…In addition, their carbon walls are often relatively thick such that the accessibility of the micropores may be restricted. The third method is the templating synthesis starting from molecular precursors [35][36][37][38]. Various templates can be adopted to confine the carbonization of different precursors.…”

Section: Introductionmentioning

confidence: 99%

“…Various templates can be adopted to confine the carbonization of different precursors. In particular, the dual templating approach, in which colloid nanospheres and surfactants act as the hard and soft templates, is capable of synthesizing ordered hierarchical structures with uniform and controllable pore sizes [35,[39][40][41][42]. Nevertheless, this templating method is complicated, costly and time-consuming.…”

Section: Introductionmentioning

confidence: 99%

“…This method may cause uneven distribution of N and structure change. The more common method is in situ doping by directly pyrolysis of a single N-containing organic precursor or precursor mixture [35,60,[63][64][65][66][67]. Although a series of porous N-doped carbon materials have been reported, the construction of threedimensional HPCs with ultrahigh surface areas, large pore volumes, and high N contents sustained at high carbonization temperatures is still highly demanded.…”

Section: Introductionmentioning

confidence: 99%

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A Molecular Foaming and Activation Strategy to Porous N-Doped Carbon Foams for Supercapacitors and CO2 Capture

et al. 2020

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HIGHLIGHTS• An in situ molecular foaming and activation strategy is designed and investigated for the synthesis of hierarchically porous N-doped carbon foams (HPNCFs).• The prepared HPNCFs possess 3D macropores, uniform micropores and mesopores, ultrahigh surface areas and high N contents and show high performances in supercapacitors and CO 2 capture.ABSTRACT Hierarchically porous carbon materials are promising for energy storage, separation and catalysis. It is desirable but fairly challenging to simultaneously create ultrahigh surface areas, large pore volumes and high N contents in these materials. Herein, we demonstrate a facile acid-base enabled in situ molecular foaming and activation strategy for the synthesis of hierarchically macro-/meso-/microporous N-doped carbon foams (HPNCFs). The key design for the synthesis is the selection of histidine (His) and potassium bicarbonate (PBC) to allow the formation of 3D foam structures by in situ foaming, the PBC/His acid-base reaction to enable a molecular mixing and subsequent a uniform chemical activation, and the stable imidazole moiety in His to sustain high N contents after carbonization. The formation mechanism of the HPNCFs is studied in detail. The prepared HPNCFs possess 3D macroporous frameworks with thin well-graphitized carbon walls, ultrahigh surface areas (up to 3200 m 2 g −1 ), large pore volumes (up to 2.0 cm 3 g −1 ), high micropore volumes (up to 0.67 cm 3 g −1 ), narrowly distributed micropores and mesopores and high N contents (up to 14.6 wt%) with pyrrolic N as the predominant N site. The HPNCFs are promising for supercapacitors with high specific capacitances (185-240 F g −1 ), good rate capability and excellent stability. They are also excellent for CO 2 capture with a high adsorption capacity (~ 4.13 mmol g −1 ), a large isosteric heat of adsorption (26.5 kJ mol −1 ) and an excellent CO 2 /N 2 selectivity (~ 24). on the two isotherms wherein the adsorption capacities are the same.

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Pyrrolic‐Type Nitrogen‐Doped Hierarchical Macro/Mesoporous Carbon as a Bifunctional Host for High‐Performance Thick Cathodes for Lithium‐Sulfur Batteries

Cited by 43 publications

References 54 publications

Lithium–Sulfur Batteries under Lean Electrolyte Conditions: Challenges and Opportunities

Lithium–Sulfur Batteries under Lean Electrolyte Conditions: Challenges and Opportunities

Sustainable Synthesis of N‐Doped Hollow Porous Carbon Spheres via a Spray‐Drying Method for Lithium‐Sulfur Storage with Ultralong Cycle Life

A Molecular Foaming and Activation Strategy to Porous N-Doped Carbon Foams for Supercapacitors and CO2 Capture

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