Potassium compound-assistant synthesis of multi-heteroatom doped ultrathin porous carbon nanosheets for high performance supercapacitors

et al. 2019

Adv Funct Materials

Hierarchical porous materials (HPM) have been widely used to enhance electrochemical performance in different fields of application, since their porous structures benefit electrolyte infiltration and ion diffusion. However, the realization of multidimension-controllable synthesis of HPM, including material category, material components, supporting substrates, as well as pore sizes/ distributions, is still a huge challenge. Herein, a novel concept is proposed, for the first time, on the geometry structure of HPM bioinspired by natural ant nests, which features 3D interlaced and well-interconnected porous structures. Moreover, a facile and universal approach is developed to the multidimensioncontrollable synthesis of ant nest-structural HPM. Further investigation shows that the in situ construction of carbon-based ant nests onto porous current collectors to fabricate the integrated electrode for supercapacitors could induce nearly 70% and 45% enhancement on the specific capacitance compared to the common powder and freestanding materials, respectively. Moreover, this synthesis route can be facilely extended to obtain the ant neststructural CuO x , which exhibits fivefold enhancement in sensitivity for glucose detection. Such biomimetic hierarchical porous architectures are of great significance in the field of electrochemical applications.

Section: Resultsmentioning

confidence: 76%

Multidimension‐Controllable Synthesis of Ant Nest‐Structural Electrode Materials with Unique 3D Hierarchical Porous Features toward Electrochemical Applications

Miao

Lü

et al. 2019

Adv Funct Materials

“…In addition, the low intrinsic Ohmic resistance ( R s , 2.9 Ω) and interfacial charge transfer resistance ( R ct , 0.9 Ω) in Nyquist plots of ALC‐6000‐800 result in an impressively low R ESR of 5.2 Ω (Figure f). This result is also smaller than those in reported high‐performance EDLCs of ionic liquid electrolytes (8–15 Ω) . The rapid response of ALC‐600‐800 supercapacitor is further supported by a small relaxation time τ 0 of 4.18 s (Figure f).…”

Section: Resultsmentioning

confidence: 66%

“…From the TGA spectra (Figure a), thermal decomposition starts with the loss of bound water at 120–180 °C . The decomposition of the aliphatic groups, especially the Cγ terminal hydroxymethyl groups, then boosts the mass loss at 200–300 °C . The peak temperatures (maximum rate of mass loss) of AL‐6000, AL‐12000, AL‐24000, AL‐32000 occur at 350, 365, 377 and 394 °C, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Despite that the micropores will be partially blocked at high current density, the improved wettability of ALC‐32000‐800 owing to the great number of heteroatoms alleviates the difficult ion diffusion and provide more accessible surface area for charge accumulation . The electrochemical activity enhanced by the polarized sites of hydroxyl, carboxylic, carbonyl and N5/N6 groups further facilitates the remarkable specific capacitance of ALC‐32000‐800 . Therefore, the 3D oriented N/O co‐doped porous carbon of ALC‐32000‐800 is found with competitive performance in the aqueous electrolyte (Table S4).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Structural Rigging of Lignin Precursors for Customized Porous and Graphene‐Like Carbons towards Enhanced Supercapacitive Performance in Aqueous and Non‐Aqueous Electrolytes

Liu

et al. 2019

ChemElectroChem

Maximum supercapacitive performance in different electrolytes is desirable in the design of advanced carbon materials but still challenged by the conflicting properties of electrolytes. Herein, a practical and scalable strategy to customize carbon materials for aqueous and non‐aqueous electrolytes was proposed via structural rigging of lignin precursors. The resultant graphene‐like hierarchical porous carbon sheets from low‐molecular‐weight lignin exhibit a high electrical conductivity of 17.8 S cm−1, a prominent capacitance of 245 F g−1 at 1 A g−1 and impressive chemical stability in the symmetric supercapacitor of ionic liquid electrolyte. The top‐level energy density of 96.7 Wh kg−1 at a power density of 0.9 kW kg−1 and 48.5 Wh kg−1 at 20.5 kW kg−1 is also obtained. In contrast, the 3D oriented N/O co‐doped porous carbon composed of high‐molecular‐weight lignin possesses high specific surface area (>2400 m2 g−1), regulated micropores and rich heteroatoms for remarkable specific capacitances of 402 F g−1 and 306 F g−1 at 1.0 A g−1 in three‐ and two‐electrode configurations of aqueous electrolyte, respectively. The established formation mechanisms further extend the exploration of highly plastic lignin precursors for diverse energy storage systems.

“…Recently,t wo-dimensional (2D) carbonm aterials have drawn increasing interestf or their application in electrocatalysis owingt ot heir high conductivity,l arge specific area,a nd highly open and exposed surfaces. [19][20][21][22][23][24] Compared to the previously reported3 Dp orousc arbon-based electrocatalytic materials in the literature, [25,26] 2D carbon materials theoretically possess a more accessible surface area and significantly higher percentage of exposed catalytic active sites for ORR reactants, thereby offering ap ortfolio of highly attractive electrocatalysts towards ORR. [27,28] Severalapproaches to synthesize 2D carbon materials have been reported, including hard-ands oft-template synthesis as well as the constructiono f2 Ds tructured carbonization precursors.…”

Section: Introductionmentioning

confidence: 99%

Ice/Salt‐Assisted Synthesis of Ultrathin Two‐Dimensional Micro/Mesoporous Iron and Nitrogen Co‐Doped Carbon as an Efficient Electrocatalyst for Oxygen Reduction

Iyoda

et al. 2019

Chemistry A European J

Self Cite

An ice/salt‐assisted strategy has been developed to achieve the green and efficient synthesis of ultrathin two‐dimensional (2D) micro/mesoporous carbon nanosheets (CNS) with the dominant active moieties of Fe−N4 (Fe‐N‐CNS) as high‐performance electrocatalysts for the oxygen reduction reaction (ORR). The strategy involves freeze‐drying a mixture of iron porphyrin and KCl salt using ice as template followed by a confined pyrolysis with KCl as an independent sealed nanoreactor to facilitate the formation of 2D carbon nanosheets, N incorporation, and porosity creation. The well‐defined assembly of ultrathin 2D carbon nanosheets ensures high utilization of D1 and D3 Fe−N4 active sites, and effectively promotes the mass transport of ORR reactants by virtue of the pronounced mesoporous structure. The resulting Fe‐N‐CNS electrocatalyst was shown to exhibit superior ORR activity, better electrochemical durability, and methanol tolerance towards ORR in alkaline electrolyte relative to the commercial Pt/C electrocatalyst.