Hierarchically porous graphene for batteries and supercapacitors

2018 ◽  
Vol 42 (8) ◽  
pp. 5634-5655 ◽  
Author(s):  
Shimeles T. Bulbula ◽  
Yi Lu ◽  
Ying Dong ◽  
Xiao-Yu Yang
Keyword(s):  
Thermal Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Specific Capacity ◽  
Large Specific Surface Area ◽  
Storage Devices ◽  
Porous Graphene ◽  
Hierarchical Porous ◽  
Electrochemical Storage

Hierarchical porous graphene based materials are explored for their application as electrochemical storage devices due to their large specific surface area, high electrical and thermal conductivity, and excellent specific capacity.

Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors

2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Large Specific Surface Area ◽  
Composite Aerogel

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.

Fabrication of Biomass-Derived N, S Co-doped Carbon with Hierarchically Porous Architecture for High Performance Supercapacitor

NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050096
Author(s):  
Minhua Jiang ◽  
Xiaofang Yu ◽  
Ruirui Gao ◽  
Tao Yang ◽  
Zhaoxiu Xu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Materials ◽  
Large Specific Surface Area ◽  
Hierarchically Porous ◽  
Porous Architecture ◽  
Hierarchical Porous ◽  
Hierarchical Porous Carbons ◽  
Co Doped

Multi-element doped porous carbon materials are considered as one of the most promising electrode materials for supercapacitors due to their large specific surface area, abundant mesoporous structure, heteroatom doping and good conductivity. Herein, we propose a very simple and effective strategy to prepare nitrogen, sulfur co-doped hierarchical porous carbons (N-S-HPC) by one-step pyrolysis strategy. The effect of sole dopants as a precursor was a major factor in the transformation process. The optimized N-S-HPC-2 possesses a typical hierarchically porous framework (micropores, mesopores and macropores) with a large specific surface area (1284.87[Formula: see text]m2 g[Formula: see text] and N (4.63 atomic %), S (0.53 atomic %) doping. As a result, the N-S-HPC-2 exhibits excellent charge storage capacity with a high gravimetric capacitance of 360[Formula: see text]F g[Formula: see text] (1 [Formula: see text]A g[Formula: see text] in three-electrode systems and 178[Formula: see text]F g[Formula: see text] in two-electrode system and long-term cycling life with 87% retention after 10,000 cycles in KOH electrolyte.

Nanoflake assembled hierarchical porous flower-like α-Fe2O3 with large specific surface area for enhanced acetone sensing

2020 ◽  
Vol 13 (06) ◽  
pp. 2051038
Author(s):  
Jianxia Zhang ◽  
Li Liu ◽  
Xiaonian Tang ◽  
Dan Sun ◽  
Chunxia Tian ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Gas Sensing ◽  
High Porosity ◽  
Large Specific Surface Area ◽  
Minimum Concentration ◽  
Maximum Value ◽  
Hierarchical Porous

High porosity [Formula: see text]-Fe2O3 has attracted a lot of attention due to its exceptional structure. In this paper, nanoflake assembled hierarchical porous flower-like [Formula: see text]-Fe2O3 was prepared by hydrothermal and calcination methods without any additional templates. Scanning electron microscopy (SEM) morphological characterization results show that with the increase of calcination temperature (400∘C, 450∘C, 500∘C, 550∘C, 600∘C), pores appeared. However, the results of nitrogen adsorption show that the specific surface area of the [Formula: see text]-Fe2O3 reaches the maximum value (52.19[Formula: see text]m2/g) when the calcination temperature is 500∘C. The gas sensing performance of flower-like [Formula: see text]-Fe2O3 with different calcination temperature is compared, interestingly, with the increase of calcination temperature, the response of the samples increased first and then decreased, and reached the maximum value (44.2–100 parts per million (ppm) acetone) when the calcination temperature was 500∘C. The minimum concentration for acetone was 200 ppb (response value is 2.0). Moreover, calcined at 500∘C, hierarchical porous [Formula: see text]-Fe2O3 has a fast response recovery (4/25 s) and low working temperature (210∘C). These excellent gas sensing properties are mainly due to porous structure, large specific surface area, and oxygen vacancies on the surface, which make it a promising material for acetone sensors.

A facile low-temperature synthesis of hierarchical porous Co3O4 micro/nano structures derived from ZIF-67 assisted by ammonium perchlorate

2019 ◽  
Vol 6 (3) ◽  
pp. 715-722 ◽  
Author(s):  
Kun Zhao ◽  
Haitao Li ◽  
Shouqin Tian ◽  
Wenjuan Yang ◽  
Xiaoxia Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Ammonium Perchlorate ◽  
Specific Surface Area ◽  
Large Specific Surface Area ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Nano Structures ◽  
Hierarchical Porous

Sub-micro hierarchical porous Co3O4 dodecahedra with a large specific surface area (106.11 m2 g−1) were synthesized by the thermolysis of ZIF-67 at a low temperature of 268 °C assisted by ammonium perchlorate (AP).

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

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