scholarly journals Direct electrochemical generation of supercooled sulfur microdroplets well below their melting temperature

2019 ◽  
Vol 116 (3) ◽  
pp. 765-770 ◽  
Author(s):  
Nian Liu ◽  
Guangmin Zhou ◽  
Ankun Yang ◽  
Xiaoyun Yu ◽  
Feifei Shi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Electrochemical Cell ◽  
Supercooled Liquid ◽  
High Energy ◽  
Liquid Sulfur ◽  
Electrochemical Generation ◽  
Precise Control ◽  
Electrochemical Current ◽  
In Operando ◽  
Lithium Sulfur

Supercooled liquid sulfur microdroplets were directly generated from polysulfide electrochemical oxidation on various metal-containing electrodes. The sulfur droplets remain liquid at 155 °C below sulfur’s melting point (Tm = 115 °C), with fractional supercooling change (Tm − Tsc)/Tm larger than 0.40. In operando light microscopy captured the rapid merging and shape relaxation of sulfur droplets, indicating their liquid nature. Micropatterned electrode and electrochemical current allow precise control of the location and size of supercooled microdroplets, respectively. Using this platform, we initiated and observed the rapid solidification of supercooled sulfur microdroplets upon crystalline sulfur touching, which confirms supercooled sulfur’s metastability at room temperature. In addition, the formation of liquid sulfur in electrochemical cell enriches lithium-sulfur-electrolyte phase diagram and potentially may create new opportunities for high-energy Li-S batteries.

scholarly journals Supercooled liquid sulfur maintained in three-dimensional current collector for high-performance Li-S batteries

2020 ◽  
Vol 6 (21) ◽  
pp. eaay5098 ◽  
Author(s):  
Guangmin Zhou ◽  
Ankun Yang ◽  
Guoping Gao ◽  
Xiaoyun Yu ◽  
Jinwei Xu ◽  
...  
Keyword(s):  
High Performance ◽  
Critical Role ◽  
Three Dimensional ◽  
Current Collector ◽  
Reversible Capacity ◽  
Supercooled Liquid ◽  
High Energy ◽  
Liquid Sulfur ◽  
Sulfur Species ◽  
Solid Liquid

In lithium-sulfur (Li-S) chemistry, the electrically/ionically insulating nature of sulfur and Li2S leads to sluggish electron/ion transfer kinetics for sulfur species conversion. Sulfur and Li2S are recognized as solid at room temperature, and solid-liquid phase transitions are the limiting steps in Li-S batteries. Here, we visualize the distinct sulfur growth behaviors on Al, carbon, Ni current collectors and demonstrate that (i) liquid sulfur generated on Ni provides higher reversible capacity, faster kinetics, and better cycling life compared to solid sulfur; and (ii) Ni facilitates the phase transition (e.g., Li2S decomposition). Accordingly, light-weight, 3D Ni-based current collector is designed to control the deposition and catalytic conversion of sulfur species toward high-performance Li-S batteries. This work provides insights on the critical role of the current collector in determining the physical state of sulfur and elucidates the correlation between sulfur state and battery performance, which will advance electrode designs in high-energy Li-S batteries.

scholarly journals Understanding Sulfur Redox Mechanisms in Different Electrolytes for Room-Temperature Na–S Batteries

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Hanwen Liu ◽  
Wei-Hong Lai ◽  
Qiuran Yang ◽  
Yaojie Lei ◽  
Can Wu ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Surface ◽  
Reversible Capacity ◽  
High Loading ◽  
Side Reactions ◽  
Liquid Sulfur ◽  
Shuttle Effect ◽  
Loading Ratio ◽  
Solid Liquid ◽  
Sulfur Cathodes

Abstract This work reports influence of two different electrolytes, carbonate ester and ether electrolytes, on the sulfur redox reactions in room-temperature Na–S batteries. Two sulfur cathodes with different S loading ratio and status are investigated. A sulfur-rich composite with most sulfur dispersed on the surface of a carbon host can realize a high loading ratio (72% S). In contrast, a confined sulfur sample can encapsulate S into the pores of the carbon host with a low loading ratio (44% S). In carbonate ester electrolyte, only the sulfur trapped in porous structures is active via ‘solid–solid’ behavior during cycling. The S cathode with high surface sulfur shows poor reversible capacity because of the severe side reactions between the surface polysulfides and the carbonate ester solvents. To improve the capacity of the sulfur-rich cathode, ether electrolyte with NaNO3 additive is explored to realize a ‘solid–liquid’ sulfur redox process and confine the shuttle effect of the dissolved polysulfides. As a result, the sulfur-rich cathode achieved high reversible capacity (483 mAh g−1), corresponding to a specific energy of 362 Wh kg−1 after 200 cycles, shedding light on the use of ether electrolyte for high-loading sulfur cathode.

Sulfur vacancies in Co9S8-x/N-doped graphene enhancing electrochemical kinetics to high-performance lithium sulfur batteries

2021 ◽  
Author(s):  
Haojie Li ◽  
Yihua Song ◽  
Kai Xi ◽  
Wei Wang ◽  
Sheng Liu ◽  
...  
Keyword(s):  
Cathode Materials ◽  
High Performance ◽  
Catalytic Conversion ◽  
High Energy ◽  
Electrochemical Kinetics ◽  
Lithium Sulfur Batteries ◽  
Doped Graphene ◽  
Sulfur Battery ◽  
Areal Capacity ◽  
Lithium Sulfur

A sufficient areal capacity is necessary for achieving high-energy lithium sulfur battery, which requires high enough sulfur loading in cathode materials. Therefore, kinetically fast catalytic conversion of polysulfide intermediates is...

scholarly journals Research Progress toward Room Temperature Sodium Sulfur Batteries: A Review

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1535
Author(s):  
Yanjie Wang ◽  
Yingjie Zhang ◽  
Hongyu Cheng ◽  
Zhicong Ni ◽  
Ying Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Room Temperature ◽  
High Energy ◽  
Safety Performance ◽  
High Energy Density ◽  
Research Progress ◽  
Storage Performance ◽  
Sulfur Battery ◽  
Sodium Sulfur Battery ◽  
Sodium Sulfur

Lithium metal batteries have achieved large-scale application, but still have limitations such as poor safety performance and high cost, and limited lithium resources limit the production of lithium batteries. The construction of these devices is also hampered by limited lithium supplies. Therefore, it is particularly important to find alternative metals for lithium replacement. Sodium has the properties of rich in content, low cost and ability to provide high voltage, which makes it an ideal substitute for lithium. Sulfur-based materials have attributes of high energy density, high theoretical specific capacity and are easily oxidized. They may be used as cathodes matched with sodium anodes to form a sodium-sulfur battery. Traditional sodium-sulfur batteries are used at a temperature of about 300 °C. In order to solve problems associated with flammability, explosiveness and energy loss caused by high-temperature use conditions, most research is now focused on the development of room temperature sodium-sulfur batteries. Regardless of safety performance or energy storage performance, room temperature sodium-sulfur batteries have great potential as next-generation secondary batteries. This article summarizes the working principle and existing problems for room temperature sodium-sulfur battery, and summarizes the methods necessary to solve key scientific problems to improve the comprehensive energy storage performance of sodium-sulfur battery from four aspects: cathode, anode, electrolyte and separator.

scholarly journals Precise Control of CsPbBr3 Perovskite Nanocrystal Growth at Room Temperature: Size Tunability and Synthetic Insights

2021 ◽  
Vol 33 (7) ◽  
pp. 2387-2397
Author(s):  
Alasdair A. M. Brown ◽  
Parth Vashishtha ◽  
Thomas J. N. Hooper ◽  
Yan Fong Ng ◽  
Gautam V. Nutan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Precise Control ◽  
Nanocrystal Growth

scholarly journals Confine sulfur in double-hollow carbon sphere integrated with carbon nanotubes for advanced lithium–sulfur batteries

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Maru Dessie Walle ◽  
You-Nian Liu
Keyword(s):  
Carbon Nanotubes ◽  
Coulombic Efficiency ◽  
Specific Capacity ◽  
High Energy ◽  
High Energy Density ◽  
Carbon Sphere ◽  
Hollow Carbon Sphere ◽  
Lithium Sulfur Batteries ◽  
Hollow Carbon ◽  
Lithium Sulfur

AbstractThe lithium–sulfur (Li–S) batteries are promising because of the high energy density, low cost, and natural abundance of sulfur material. Li–S batteries have suffered from severe capacity fading and poor cyclability, resulting in low sulfur utilization. Herein, S-DHCS/CNTs are synthesized by integration of a double-hollow carbon sphere (DHCS) with carbon nanotubes (CNTs), and the addition of sulfur in DHCS by melt impregnations. The proposed S-DHCS/CNTs can effectively confine sulfur and physically suppress the diffusion of polysulfides within the double-hollow structures. CNTs act as a conductive agent. S-DHCS/CNTs maintain the volume variations and accommodate high sulfur content 73 wt%. The designed S-DHCS/CNTs electrode with high sulfur loading (3.3 mg cm−2) and high areal capacity (5.6 mAh mg cm−2) shows a high initial specific capacity of 1709 mAh g−1 and maintains a reversible capacity of 730 mAh g−1 after 48 cycles at 0.2 C with high coulombic efficiency (100%). This work offers a fascinating strategy to design carbon-based material for high-performance lithium–sulfur batteries.

scholarly journals Room‐Temperature Sodium–Sulfur Batteries and Beyond: Realizing Practical High Energy Systems through Anode, Cathode, and Electrolyte Engineering

2021 ◽  
Vol 11 (14) ◽  
pp. 2003493
Author(s):  
Alex Yong Sheng Eng ◽  
Vipin Kumar ◽  
Yiwen Zhang ◽  
Jianmin Luo ◽  
Wenyu Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Energy Systems ◽  
High Energy ◽  
Sodium Sulfur
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