scholarly journals Carbon-Coated Three-Dimensional MXene/Iron Selenide Ball with Core–Shell Structure for High-Performance Potassium-Ion Batteries

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Su Hyun Yang ◽  
Yun Jae Lee ◽  
Heemin Kang ◽  
Seung-Keun Park ◽  
Yun Chan Kang

AbstractTwo-dimensional (2D) MXenes are promising as electrode materials for energy storage, owing to their high electronic conductivity and low diffusion barrier. Unfortunately, similar to most 2D materials, MXene nanosheets easily restack during the electrode preparation, which degrades the electrochemical performance of MXene-based materials. A novel synthetic strategy is proposed for converting MXene into restacking-inhibited three-dimensional (3D) balls coated with iron selenides and carbon. This strategy involves the preparation of Fe2O3@carbon/MXene microspheres via a facile ultrasonic spray pyrolysis and subsequent selenization process. Such 3D structuring effectively prevents interlayer restacking, increases the surface area, and accelerates ion transport, while maintaining the attractive properties of MXene. Furthermore, combining iron selenides and carbon with 3D MXene balls offers many more sites for ion storage and enhances the structural robustness of the composite balls. The resultant 3D structured microspheres exhibit a high reversible capacity of 410 mAh g−1 after 200 cycles at 0.1 A g−1 in potassium-ion batteries, corresponding to the capacity retention of 97% as calculated based on 100 cycles. Even at a high current density of 5.0 A g−1, the composite exhibits a discharge capacity of 169 mAh g−1.

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 695 ◽  
Author(s):  
Yijun Liu ◽  
Ying He ◽  
Elif Vargun ◽  
Tomas Plachy ◽  
Petr Saha ◽  
...  

To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materials for lithium-ion batteries (LIBs), a facile strategy is developed to construct three-dimensional (3D) hierarchical porous Ti3C2/bimetal-organic framework (NiCo-MOF) nanoarchitectures as anodes for high-performance LIBs. 2D Ti3C2 nanosheets are coupled with NiCo-MOF nanoflakes induced by hydrogen bonds to form 3D Ti3C2/NiCo-MOF composite films through vacuum-assisted filtration technology. The morphology and electrochemical properties of Ti3C2/NiCo-MOF are influenced by the mass ratio of MOF to Ti3C2. Owing to the interconnected porous structures with a high specific surface area, rapid charge transfer process, and Li+ diffusion rate, the Ti3C2/NiCo-MOF-0.4 electrode delivers a high reversible capacity of 402 mAh g−1 at 0.1 A g−1 after 300 cycles; excellent rate performance (256 mAh g−1 at 1 A g−1); and long-term stability with a capacity retention of 85.7% even after 400 cycles at a high current density, much higher than pristine Ti3C2 MXene. The results highlight that Ti3C2/NiCo-MOF have great potential in the development of high-performance energy storage devices.


Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1137
Author(s):  
Can Wang ◽  
Xunlong Yuan ◽  
Huiyun Tan ◽  
Shuofeng Jian ◽  
Ziting Ma ◽  
...  

LiFePO4 (LFPO)has great potential as the cathode material for lithium-ion batteries; it has a high theoretical capacity (170 m·A·h·g−1), high safety, low toxicity and good economic benefits. However, low conductivity and a low diffusion rate inhibit its future development. To overcome these weaknesses, three-dimensional carbon-coated LiFePO4 that incorporates a high capacity, superior conductivity and low volume expansion enables faster electron transport channels. The use of Cetyltrimethyl Ammonium Bromid (CTAB) modification only requires a simple water bath and sintering, without the need to add a carbon source in the LFPO synthesis process. In this way, the electrode shows excellent reversible capacity, as high as 159.8 m·A·h·g−1 at 2 C, superior rate capability with 97.3 m·A·h·g−1at 5 C and good cycling ability, preserving ~84.2% capacity after 500 cycles. By increasing the ion transport rate and enhancing the structural stability of LFPO nanoparticles, the LFPO-positive electrode achieves excellent initial capacity and cycle life through cost-effective and easy-to-implement carbon coating. This simple three-dimensional carbon-coated LiFePO4 provides a new and simple idea for obtaining comprehensive and high-performance electrode materials in the field of lithium cathode materials.


NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650015 ◽  
Author(s):  
Tingting Chen ◽  
Yong Fan ◽  
Guangning Wang ◽  
Jing Zhang ◽  
Huixin Chuo ◽  
...  

The composite supercapacitor electrodes were rationally fabricated by facile electrochemical deposition of polypyrrole (PPy) on NiCo2O4 nanowire arrays which were grown radially on carbon fiber (CF). When used as electrodes in supercapacitors, the composite nanostructures demonstrated prominent electrochemical performances with a high areal capacitance (1.44[Formula: see text]F/cm2 at a current density of 2[Formula: see text]mA/cm2), a good rate capability (80.5% when the current density increases from 2[Formula: see text]mA/cm2 to 20[Formula: see text]mA/cm2), and a good cycling ability (85% of the initial specific capacitance remained after 5000 cycles at a high current density of 10[Formula: see text]mA/cm2). The excellent electrochemical performance of NiCo2O4@PPy nanostructures can be mainly ascribed to the good electrical conductivity of PPy, the enhanced adherent force between electrode materials and CF to hold the electrode fragments together by means of NiCo2O4 nanowires, the short ion diffusion pathway in ordered porous NiCo2O4 nanowires and the three-dimensional nanostructures.


Author(s):  
Tingting Xia ◽  
Chengfei Xu ◽  
Pengfei Dai ◽  
Xiaoyun Li ◽  
Riming Lin ◽  
...  

Three-dimensional (3D) conductive polymers are promising conductive matrices for electrode materials toward electrochemical energy storage. However, their fragile nature and weak binding forces with active materials could not guarantee long-term...


2021 ◽  
Author(s):  
Feiqiang Guo ◽  
Yinbo Zhan ◽  
Xiaopeng Jia ◽  
Huiming Zhou ◽  
Shuang Liang ◽  
...  

Using Sargassum as the precursor, a novel approach was developed to synthesize three-dimensional porous carbons as high-performance electrode materials for supercapacitors via KOH activation and subsequent nitrogen-doping employing melamine as...


2017 ◽  
Vol 5 (37) ◽  
pp. 19991-19996 ◽  
Author(s):  
Xuecheng Cao ◽  
Zhihui Sun ◽  
Xiangjun Zheng ◽  
Jinghua Tian ◽  
Chao Jin ◽  
...  

The application of MnCo2O4 (MCO) decorated Ti4O7 as a carbon-free cathode for Li–O2 batteries is reported for the first time. The high performance of Ti4O7/MCO cathode is attributed to the high electronic conductivity of Ti4O7, the high electrocatalytic activity of MCO and the synergistic interaction between Ti4O7 and MCO toward ORR and OER.


2021 ◽  
Vol 22 (20) ◽  
pp. 11041
Author(s):  
Yajing Yan ◽  
Yanxu Chen ◽  
Yongyan Li ◽  
Xiaoyu Wu ◽  
Chao Jin ◽  
...  

By virtue of the high theoretical capacity of Si, Si-related materials have been developed as promising anode candidates for high-energy-density batteries. During repeated charge/discharge cycling, however, severe volumetric variation induces the pulverization and peeling of active components, causing rapid capacity decay and even development stagnation in high-capacity batteries. In this study, the Si/Fe2O3-anchored rGO framework was prepared by introducing ball milling into a melt spinning and dealloying process. As the Li-ion battery (LIB) anode, it presents a high reversible capacity of 1744.5 mAh g−1 at 200 mA g−1 after 200 cycles and 889.4 mAh g−1 at 5 A g−1 after 500 cycles. The outstanding electrochemical performance is due to the three-dimensional cross-linked porous framework with a high specific surface area, which is helpful to the transmission of ions and electrons. Moreover, with the cooperation of rGO, the volume expansion of Si is effectively alleviated, thus improving cycling stability. The work provides insights for the design and preparation of Si-based materials for high-performance LIB applications.


2020 ◽  
Vol 8 (7) ◽  
pp. 4007-4016 ◽  
Author(s):  
Xiaoyan Wang ◽  
Shaofeng Wang ◽  
Kaixiang Shen ◽  
Shenggong He ◽  
Xianhua Hou ◽  
...  

Phosphorus-doped hollow carbon nanorods with high electronic conductivity can maintain excellent structural stability and endow outstanding electrochemical performance in sodium-based dual-ion batteries.


Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1952 ◽  
Author(s):  
Santanu Mukherjee ◽  
Shakir Bin Mujib ◽  
Davi Soares ◽  
Gurpreet Singh

Sodium ion batteries (SIBs) are being billed as an economical and environmental alternative to lithium ion batteries (LIBs), especially for medium and large-scale stationery and grid storage. However, SIBs suffer from lower capacities, energy density and cycle life performance. Therefore, in order to be more efficient and feasible, novel high-performance electrodes for SIBs need to be developed and researched. This review aims to provide an exhaustive discussion about the state-of-the-art in novel high-performance anodes and cathodes being currently analyzed, and the variety of advantages they demonstrate in various critically important parameters, such as electronic conductivity, structural stability, cycle life, and reversibility.


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