Surface‐Driven Energy Storage Behavior of Dual‐Heteroatoms Functionalized Carbon Material

“…During the sodiation process, the charge transfer resistance ( R CT ) is on an upward trend derived from the formation of NaS 2 , accompanying with heteroatomic phase transformation process. Phase transformation behavior would leading to active sites volume expansion, and hence slightly expanding the lattice spacing of carbon layer accompany with the enlargement of resistance . During the desodiation process, the R CT of each voltage points are on opposite trend, which is attributed to lattice contraction.…”

Section: Resultsmentioning

confidence: 99%

“…Nitrogen is the most commonly investigated heteroatom owing to their significant improvement of conductivity and surface wettability between electrode interface and electrolyte, while sulfur doping especially in amorphous carbon prominently enhances sodium storage capacity due to its considerable faraday behavior . Additionally, sulfur doping can also slightly expand the interlayer distances, which is of great assistance for sodium insertion behavior . In our previous work, various chemical doping carbonaceous anodes with multiple heteroatoms were derived by different carbon/heteroatoms sources .…”

Section: Introductionmentioning

confidence: 99%

Accurate Control Multiple Active Sites of Carbonaceous Anode for High Performance Sodium Storage: Insights into Capacitive Contribution Mechanism

Liang

et al. 2020

Advanced Energy Materials

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Heteroatom doping is widely recognized as an appealing strategy to break the capacitance limitation of carbonaceous materials toward sodium storage. However, the concrete effects, especially for heteroatomic phase transformation, during the sodium storage reaction remain a confusing topic. Here, a novel hypercrosslinked polymerization approach is demonstrated to fabricate pyrrole/thiophene hypercrosslinked microporous copolymer and further give porous carbonaceous materials with accurately regulated N/S dual doping corresponding to starting feeding ratios. Significantly, the N doping contributes to the conductivity and surface wettability, while the S doping is bridged to build stable active sites, which can be electrochemically converted into mercaptan anions via faraday reaction and further enhancing reversible capacities. Meanwhile, the abundant S doping can also conduce to the expanded interlayer spacing to shorten the ions diffusion distance, thus optimizing the reaction kinetic. As a result, the N0.2S0.8‐micro‐dominant porous carbon delivers the highest reversible capacity of 521 mAh g−1 at 100 mA g−1 and excellent cyclic stability over 2000 cycles at 2000 mA g−1 with a capacity decay of 0.0145 mAh g−1 per cycle. This work is anticipated to provide an in‐depth understanding of capacitance contribution and illuminate the heteroatomic phase transformation during sodium storage reactions for doping carbonaceous anodes.

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“…Nyquist plots display a compressed semicircle in high‐frequency region and a straight line in low‐frequency region, corresponding to charge‐transfer resistance at interface and mass transfer of lithium ions, respectively. [ 26 ] In general, the larger diameter of the semicircle means a larger charge transfer resistance. [ 27 ] In the high‐frequency domain, the apparent differences of radius at the same potentials indicate that the architecture of the CeO 2 @Carbon/SNBT facilitates rapid charge transfer.…”

Section: Resultsmentioning

confidence: 99%

Organic–Rare Earth Hybrid Anode with Superior Cyclability for Lithium Ion Battery

Wang

Sun

et al. 2020

Adv Materials Inter

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new applications. Much effort is concentrated on design and synthesis of novel electrodes that possess high theoretical capacity, proper potential, and excellent structural stability during long-term cycling. [2] Considering the sustainable development, organic redox compounds with structural diversity should be ideal electrode materials. However, organic compounds frequently suffer from intractable technical challenges: [3] a) limited electroactive sites for Li-ions insertion/ desertion cause low specific capacity; b) lithiated products are soluble in electrolytes, leading to rapid capacity fading; c) agglomerates of organic molecules cause sluggish electrochemical kinetics. To increase Li-ions storage sites, introducing redox functional groups to organic compound represents one efficient approach to improve theoretical capacity. [4] For classical dicarboxylic compounds as anode materials, [5] they reversibly transfer two electrons during electrochemical processes. In other words, they reversibly intercalate two extra lithium ions in organic compounds during discharge process. In previous studies, we have demonstrated that when four sulfur atoms are introduced to a single carboxylate scaffold, electron delocalization and electrical conductivity were remarkably improved. Accordingly, ion storage sites are significantly increased to six, [6] resulting in an exceptional theoretical capacity.Although the problem of organic compound dissolution has been largely addressed by polymerization, [7] this approach relies on the development of multicomponent polymeric reactions of small molecules. As for polymer battery, recent reports are mainly focused on the field of π-conjugated polymer electrodes such as polythiophene, [8] polypyrrole, [9] polyphenylene, [10] and polyacetylene. [11] Clearly, these polymers have no distinct redox sites. As a result, their low doping-degrees lead to decreased theoretical capacities. Furthermore, most of the organic polymers display the morphology of agglomerates, which is not conducive to the thermodynamics and kinetics of their electrode reactions. Fortunately, incorporating nanostructured conductors (e.g., carbon and metal oxides) to form composites has been demonstrated as one effective strategy for preventing active material dissolution. [12] For instance, Zhang et al. found that the carbon layer can improve electrical conductivity and the tangled CNT network can maintain the integrity of composite electrodes (Si@C-CNTs). [13] Chen et al. used nanostructured magnesium nickel oxide (Mg 0.6 Ni 0.4 O) to prepare the Organic compounds with electroactive sites are considered as a new generation of green electrode materials for lithium ion batteries. However, exploring effective approaches to design high-capacity molecules and suppressing their solubilization remain big challenges. Herein, a functional anode architecture is first designed by using chemical bonds between organic compound and rare earth hollow structure, which enables active materials to be efficiently utilized, accelerate...

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Surface‐Driven Energy Storage Behavior of Dual‐Heteroatoms Functionalized Carbon Material

Cited by 74 publications

References 43 publications

Macroscopic synthesis of ultrafine N–doped carbon nanofibers for superior capacitive energy storage

Macroscopic synthesis of ultrafine N–doped carbon nanofibers for superior capacitive energy storage

Accurate Control Multiple Active Sites of Carbonaceous Anode for High Performance Sodium Storage: Insights into Capacitive Contribution Mechanism

Organic–Rare Earth Hybrid Anode with Superior Cyclability for Lithium Ion Battery

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