scholarly journals A Novel Synthesizing Strategy of 3D Cose2 Porous Hollow Flowers for High Performance Lithium–Sulfur Batteries

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 273
Author(s):  
Wei Xu ◽  
Qikai Wu ◽  
Zhongmei Che ◽  
Bin Fan ◽  
Dengke Zhao ◽  
...  

Redox kinetics of lithium polysulfides (LiPSs) conversion and poor electrical conductivity of sulfur during the charge-discharge process greatly inhibit the commercialization of high-performance lithium–sulfur (Li–S) batteries. Herein, we synthesized CoSe2 porous hollow flowers (CoSe2-PHF) by etching and further selenizing layered double hydroxide, which combined the high catalytic activity of transition metal compound and high electrical conductivity of selenium. The obtained CoSe2-PHF can efficiently accelerate the catalytic conversion of LiPSs, expedite the electron transport, and improve utilization of active sulfur during the charge-discharge process. As a result, with CoSe2-PHF/S-based cathodes, the Li–S batteries exhibited a reversible specific capacity of 955.8 mAh g−1 at 0.1 C and 766.0 mAh g−1 at 0.5 C, along with a relatively small capacity decay rate of 0.070% per cycle within 400 cycles at 1 C. Even at the high rate of 3 C, the specific capacity of 542.9 mAh g−1can be maintained. This work enriches the way to prepare porous composites with high catalytic activity and electrical conductivity as sulfur hosts for high-rate, long-cycle rechargeable Li–S batteries.

2014 ◽  
Vol 1606 ◽  
Author(s):  
Teruaki Nomiyama ◽  
Kenta Sakamoto ◽  
Tomohito Yoshida ◽  
Akinori Kagiyama ◽  
Yuji Horie

ABSTRACTOne of promising photorechargeable electrode, which has two functions of photovoltaic and electrical energy storage, is a composite film of mesoporous TiO2 and conducting polymer polyaniline. Galvanostatic charge/discharge characteristics of the TiO2-polyaniline composite were examined to reveal how fast the film was charged. The film with a specific capacity 60-120 mAh g–1 was found to be fully charged at high charging rate 20 mA cm–2 which is comparable to high performance solar cells. Such high charging rate was achieved by the compact polyaniline layer covering the large specific surface area of mesoporous TiO2 film.


NANO ◽  
2021 ◽  
pp. 2150029
Author(s):  
Qian Zhang ◽  
Renxia Zhu ◽  
Chenyu Zhao ◽  
Runze Fan ◽  
Yong Zhang ◽  
...  

Application of lithium-sulfur battery has been limited due to polysulfide dissolution, the insulating nature of sulfur and the volumetric strain produced during charge and discharge process. To improve the performance of Li-S batteries, two kinds of bimetallic sulfides of NiCo2S4 with flaky (F-NiCo2S4) and sea urchin-like (S-NiCo2S4) structures were synthesized by using simple hydrothermal method, which were used as sulfur carriers in lithium-sulfur batteries and showed excellent electrochemical properties. At 0.2[Formula: see text]C, both electrodes of F-NiCo2S4/S and S-NiCo2S4/S have high pristine discharge specific capacities of 986[Formula: see text]mAh[Formula: see text]g[Formula: see text] and 959[Formula: see text]mAh[Formula: see text]g[Formula: see text]. At high current density of 4[Formula: see text]C, the F-NiCo2S4/S electrode still has a high pristine discharge specific capacity of 673[Formula: see text]mAh[Formula: see text]g[Formula: see text] and a coulombic efficiency of 97.00%. The specific capacity can remain at 526[Formula: see text]mAh[Formula: see text]g[Formula: see text] with a low average attenuation of 0.17% even after 130 cycles. The excellent electrochemical performances of the cathode material can be ascribed to the synergistic effect of tubular morphology, good electrical conductivity and strong adsorption ability of NiCo2S4 matrix for polysulfide. The job provides a new scheme and material for application of lithium-sulfur batteries with high performance.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1531
Author(s):  
Haoxian Chen ◽  
Jiayi Wang ◽  
Yan Zhao ◽  
Qindan Zeng ◽  
Guofu Zhou ◽  
...  

The severe shuttle effect of soluble polysulfides hinders the development of lithium–sulfur batteries. Herein, we develop a three-dimensionally ordered macro/mesoporous (3DOM) Nb2O5/Nb4N5 heterostructure, which combines the strong adsorption of Nb2O5 and remarkable catalysis effect of Nb4N5 by the promotion “adsorption-transformation” mechanism in sulfur reaction. Furthermore, the high electrocatalytic activity of Nb4N5 facilitates ion/mass transfer during the charge/discharge process. As a result, cells with the S-Nb2O5/Nb4N5 electrode delivered outstanding cycling stability and higher discharge capacity than its counterparts. Our work demonstrates a new routine for the multifunctional sulfur host design, which offers great potential for commercial high-performance lithium–sulfur batteries.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Bo Jiang ◽  
Da Tian ◽  
Yue Qiu ◽  
Xueqin Song ◽  
Yu Zhang ◽  
...  

AbstractPrecisely regulating of the surface structure of crystalline materials to improve their catalytic activity for lithium polysulfides is urgently needed for high-performance lithium–sulfur (Li–S) batteries. Herein, high-index faceted iron oxide (Fe2O3) nanocrystals anchored on reduced graphene oxide are developed as highly efficient bifunctional electrocatalysts, effectively improving the electrochemical performance of Li–S batteries. The theoretical and experimental results all indicate that high-index Fe2O3 crystal facets with abundant unsaturated coordinated Fe sites not only have strong adsorption capacity to anchor polysulfides but also have high catalytic activity to facilitate the redox transformation of polysulfides and reduce the decomposition energy barrier of Li2S. The Li–S batteries with these bifunctional electrocatalysts exhibit high initial capacity of 1521 mAh g−1 at 0.1 C and excellent cycling performance with a low capacity fading of 0.025% per cycle during 1600 cycles at 2 C. Even with a high sulfur loading of 9.41 mg cm−2, a remarkable areal capacity of 7.61 mAh cm−2 was maintained after 85 cycles. This work provides a new strategy to improve the catalytic activity of nanocrystals through the crystal facet engineering, deepening the comprehending of facet-dependent activity of catalysts in Li–S chemistry, affording a novel perspective for the design of advanced sulfur electrodes.


Author(s):  
Xiaohui Zhao ◽  
Chonglong Wang ◽  
Ziwei Li ◽  
Xuechun Hu ◽  
Amir A. Razzaq ◽  
...  

The lithium sulfur (Li-S) batteries have a high theoretical specific capacity (1675 mAh g-1) and energy density (2600 Wh kg-1), exerting a high perspective as the next-generation rechargeable batteries for...


2021 ◽  
Vol 10 (1) ◽  
pp. 20-33
Author(s):  
Lian Wu ◽  
Yongqiang Dai ◽  
Wei Zeng ◽  
Jintao Huang ◽  
Bing Liao ◽  
...  

Abstract Fast charge transfer and lithium-ion transport in the electrodes are necessary for high performance Li–S batteries. Herein, a N-doped carbon-coated intercalated-bentonite (Bent@C) with interlamellar ion path and 3D conductive network architecture is designed to improve the performance of Li–S batteries by expediting ion/electron transport in the cathode. The interlamellar ion pathways are constructed through inorganic/organic intercalation of bentonite. The 3D conductive networks consist of N-doped carbon, both in the interlayer and on the surface of the modified bentonite. Benefiting from the unique structure of the Bent@C, the S/Bent@C cathode exhibits a high initial capacity of 1,361 mA h g−1 at 0.2C and achieves a high reversible capacity of 618.1 m Ah g−1 at 2C after 500 cycles with a sulfur loading of 2 mg cm−2. Moreover, with a higher sulfur loading of 3.0 mg cm−2, the cathode still delivers a reversible capacity of 560.2 mA h g−1 at 0.1C after 100 cycles.


2021 ◽  
Author(s):  
Haiyang Liu ◽  
Jiaxing Wang ◽  
Miao SUN ◽  
Yu Wang ◽  
Runing Zhao ◽  
...  

Abstract Lithium-sulfur (Li-S) batteries have been considered to be one of the most promising energy storage devices in the next generation. However, the insulating properties of sulfur and the shuttle effect of soluble lithium polysulfides (LiPSs) seriously hinder the practical application of Li-S batteries. In this paper, a novel porous organic polymer (HUT3) was prepared based on the polycondensation between melamine and 1,4-phenylene diisocyanate. The micro morphology of HUT3 was improved by in-situ growth on different mass fractions of rGO (5%, 10%, 15%), and the obtained HUT3-rGO composites were employed as sulfur carriers in Li-S batteries with promoted the sulfur loading ratio and lithium ion mobility. Attributed to the synergistic effect of the chemisorption of polar groups and the physical constraints of HUT3 structure, HUT3-rGO/S electrodes exhibits excellent capacity and cyclability performance. For instance, HUT3-10rGO/S electrode exhibits a high initial specific capacity of 950 mAh g-1 at 0.2 C and retains a high capacity of 707 mAh g-1 after 500 cycles at 1 C. This work emphasizes the importance of the rational design of the chemical structure and opens up a simple way for the development of cathode materials suitable for high-performance Li-S batteries.


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