scholarly journals Research Progress of NiMn Layered Double Hydroxides for Supercapacitors: A Review

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 747 ◽  
Author(s):  
Ai-Lan Yan ◽  
Xin-Chang Wang ◽  
Ji-Peng Cheng

The research on supercapacitors has been attractive due to their large power density, fast charge/discharge speed and long lifespan. The electrode materials for supercapacitors are thus intensively investigated to improve the electrochemical performances. Various transition metal layered double hydroxides (LDHs) with a hydrotalcite-like structure have been developed to be promising electrode materials. Earth-abundant metal hydroxides are very suitable electrode materials due to the low cost and high specific capacity. This is a review paper on NiMn LDHs for supercapacitor application. We focus particularly on the recent published papers using NiMn LDHs as electrode materials for supercapacitors. The preparation methods for NiMn LDHs are introduced first. Then, the structural design and chemical modification of NiMn LDH materials, as well as the composites and films derived from NiMn LDHs are discussed. These approaches are proven to be effective to enhance the performance of supercapacitor. Finally, the reports related to NiMn LDH-based asymmetric supercapacitors are summarized. A brief discussion of the future development of NiMn LDHs is also provided.

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2263 ◽  
Author(s):  
Xiaoning Wang ◽  
Dan Wu ◽  
Xinhui Song ◽  
Wei Du ◽  
Xiangjin Zhao ◽  
...  

Polyaniline has been widely used in high-performance pseudocapacitors, due to its low cost, easy synthesis, and high theoretical specific capacitance. However, the poor mechanical properties of polyaniline restrict its further development. Compared with polyaniline, functionalized carbon materials have excellent physical and chemical properties, such as porous structures, excellent specific surface area, good conductivity, and accessibility to active sites. However, it should not be neglected that the specific capacity of carbon materials is usually unsatisfactory. There is an effective strategy to combine carbon materials with polyaniline by a hybridization approach to achieve a positive synergistic effect. After that, the energy storage performance of carbon/polyaniline hybridization material has been significantly improved, making it a promising and important electrode material for supercapacitors. To date, significant progress has been made in the synthesis of various carbon/polyaniline binary composite electrode materials. In this review, the corresponding properties and applications of polyaniline and carbon hybrid materials in the energy storage field are briefly reviewed. According to the classification of different types of functionalized carbon materials, this article focuses on the recent progress in carbon/polyaniline hybrid materials, and further analyzes their corresponding properties to provide guidance for the design, synthesis, and component optimization for high-performance supercapacitors.


2021 ◽  
Author(s):  
Luomeng Zhang ◽  
Hui Xia ◽  
Shaobo Liu ◽  
Yishan Zhou ◽  
Yuefeng Zhao ◽  
...  

Abstract Layered double hydroxides as typical supercapacitor electrode materials can perform superior energy storage if the structures are well regulated. In this work, a simple one-step hydrothermal method is used to prepare diverse nickel cobalt layered double hydroxides (NiCo-LDHs), in which the different contents of urea are used to synthesize the different nanostructures of NiCo-LDHs. The results show that the decrease in urea content can effectively improve the dispersibility of NiCo-LDHs, adjust the thickness of materials and optimize the internal pore structures, thereby enhancing the capacitance performance of NiCo-LDHs. When the content of urea is reduced from 0.03 g to 0.0075 g under a fixed precursor materials mass ratio of nickel (0.06 g) to cobalt (0.02 g) of 3:1, the prepared sample NiCo-LDH-1 exhibits the thickness of 1.62 nm, and the clear thin-layer nanosheets structures and a large number of surface pores are formed, which is beneficial to the transmission of ions into the electrode material. After being prepared as a supercapacitor electrode, the NiCo-LDH-1 displays an ultra-high specific capacitance of 3982.5 F g-1 under the current density of 1 A g-1, and high capacitance retention above 93.6% after 1000 cycles of charging and discharging at a high current density of 10 A g-1. The excellent electrochemical performance of NiCo-LDH-1 is proved by assembling two-electrode asymmetric supercapacitor with carbon spheres, displaying the specific capacitance of 95 F g-1 at 1 A g-1 and the capacitance retention with 78% over 1000 cycles. As a result, it offers a facile way to control the nanostructure of NiCo-LDHs, confirms the important affection of urea on enhancing capacitive performance for supercapacitor electrode and provides the high possibility for the development of high-performance supercapacitors.


Research ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Tao Sun ◽  
Zong-Jun Li ◽  
Xin-Bo Zhang

Organic electrode materials are receiving ever-increasing research interest due to their combined advantages, including resource renewability, low cost, and environmental friendliness. However, their practical applications are still terribly plagued by low conductivity, poor rate capability, solubility in electrolyte, and low density/utilization of active groups. In response, herein, as a proof-of-concept experiment, C=N and C=O bonds are synergically integrated into the backbone of pentacene to finely tune the electronic structures of pentacene. Unexpectedly, the firstly obtained unique 5,7,11,14-tetraaza-6,13-pentacenequinone/reduced graphene oxide (TAPQ/RGO) composite exhibits superior electrochemical performances, including an ultra-stable cycling stability (up to 2400 cycles) and good rate capability (174 mAh g−1 even at a high current density of 3.2 A g−1), which might be attributed to the abundant active groups, π-conjugated molecular structure, leaf-like morphology, and the interaction between TAPQ and graphene.


2021 ◽  
Vol 02 ◽  
Author(s):  
Yonghui Zhang ◽  
Yatong Shi ◽  
Shiyu Xie ◽  
Mingming Liu ◽  
Junli Chen ◽  
...  

: Photocatalysis is a feasible technology to solve energy shortage and environmental pollution by using solar energy. Semiconductor photocatalysts with low cost, high stability and environmental friendliness are demonstrated advantages for the production of solar fuel, CO2 reduction, and degradation of pollutants. Among them, Cu2O presents numerous potential for photocatalysis because of its narrow bandgap and high activity under visible light. However, the rapid recombination of photoinduced electron-hole pairs and the instability of Cu2O under light irradiation limit its photocatalytic performance. In order to solve the above issues, researchers prefer to incorporate Cu2O with n-type semiconductors to design p-n heterojunction composites, thus regulating the band structure, promoting the separation and transfer of electrons and holes, and accelerating the redox reaction onto the surface. In this manuscript, the preparation methods of Cu2O/n-type semiconductor composites such as hydrothermal method, electrodeposition method, and in situ method are concluded, the photocatalytic applications including CO2 reduction, hydrogen production, and degradation are presented, and the catalytic mechanism like Z-scheme, p-n heterojunction, etc. are discussed, respectively. This review also proposes that there are still challenges in broadening the photocatalytic application of Cu2O/n-type semiconductor composites.


2017 ◽  
Vol 20 (4) ◽  
pp. 205-221 ◽  
Author(s):  
Weifeng Chen ◽  
Shaona Chen ◽  
Weimin Hu ◽  
Dejiang Li ◽  
Zhongxu Dai

Graphene, a two-dimensional sheet of sp2-hybridized carbon atoms packed into a honeycomb lattice, can be combined with various polymers through different methods and techniques. Polymer/graphene nanocomposites are expected to not only preserve the fa-vorable properties of graphene and polymers, but also greatly enhance the intrinsic properties due to the synergetic effect between them. In this review, the preparation approaches of graphene/polymer nanocomposites, including melt blending, solution blending, in-situ polymeri-zation and in-situ synthesis, were presented comprehensively in order to study the relationship between these approaches and the final characteristics and performances. Each approach had different influences on the final properties of the nanocomposites. The advantages and disadvantages of the preparation methods were discussed respectively. Additionally, the application researches of the polymer/graphene nanocomposites as electrochemical sensors, were introduced in detail. With regard to some important or novel sensors, the mechanisms were proposed for reference. Finally, conclusions were given and the issues waiting to be settled for further development were pointed out. The current review demonstrates that polymer/graphene nanocomposites exhibit superior electrochemical performances and will be applied practically in the field of sensor devices.


2021 ◽  
Vol 21 (3) ◽  
pp. 1493-1499
Author(s):  
Shugui Quan ◽  
Chuanqi Feng ◽  
Yao Xiao

Tin oxide/sponge carbon composite (SnO2/C) is synthesized by solvothermal reaction. The expected electrode materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectrum. Related electrochemical properties are carried out by battery comprehensive testing system. The composite could remain its specific capacity at 660.5 mAh g−1 after 200 cycles and behaved superior rate performance. The experimental results show that SnO2/C composite not only owned improved conductivity but also stable frame structure during lithiation/delithiation processes. So SnO2/C composite behaved higher reversible specific capacity and rate performance than those of pure SnO2 or SnC2O4. Based on its outstanding electrochemical performances, the SnO2/C anode electrode is a hopeful candidate for future application in lithium ion battery system.


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