scholarly journals A high-performance potassium metal battery using safe ionic liquid electrolyte

2020 ◽  
Vol 117 (45) ◽  
pp. 27847-27853
Author(s):  
Hao Sun ◽  
Peng Liang ◽  
Guanzhou Zhu ◽  
Wei Hsuan Hung ◽  
Yuan-Yao Li ◽  
...  

Potassium secondary batteries are contenders of next-generation energy storage devices owing to the much higher abundance of potassium than lithium. However, safety issues and poor cycle life of K metal battery have been key bottlenecks. Here we report an ionic liquid electrolyte comprising 1-ethyl-3-methylimidazolium chloride/AlCl3/KCl/potassium bis(fluorosulfonyl) imide for safe and high-performance batteries. The electrolyte is nonflammable and exhibits a high ionic conductivity of 13.1 mS cm−1at room temperature. A 3.6-V battery with K anode and Prussian blue/reduced graphene oxide cathode delivers a high energy and power density of 381 and 1,350 W kg−1, respectively. The battery shows an excellent cycling stability over 820 cycles, retaining ∼89% of the original capacity with high Coulombic efficiencies of ∼99.9%. High cyclability is also achieved at elevated temperatures up to 60 °C. Uniquely, robust K, Al, F, and Cl-containing passivating interphases are afforded with this electrolyte, which is key to superior battery cycling performances.

2020 ◽  
Author(s):  
Urbi Pal ◽  
Fangfang Chen ◽  
Derick Gyabang ◽  
Thushan Pathirana ◽  
Binayak Roy ◽  
...  

We explore a novel ether aided superconcentrated ionic liquid electrolyte; a combination of ionic liquid, <i>N</i>-propyl-<i>N</i>-methylpyrrolidinium bis(fluorosulfonyl)imide (C<sub>3</sub>mpyrFSI) and ether solvent, <i>1,2</i> dimethoxy ethane (DME) with 3.2 mol/kg LiFSI salt, which offers an alternative ion-transport mechanism and improves the overall fluidity of the electrolyte. The molecular dynamics (MD) study reveals that the coordination environment of lithium in the ether aided ionic liquid system offers a coexistence of both the ether DME and FSI anion simultaneously and the absence of ‘free’, uncoordinated DME solvent. These structures lead to very fast kinetics and improved current density for lithium deposition-dissolution processes. Hence the electrolyte is used in a lithium metal battery against a high mass loading (~12 mg/cm<sup>2</sup>) LFP cathode which was cycled at a relatively high current rate of 1mA/cm<sup>2</sup> for 350 cycles without capacity fading and offered an overall coulombic efficiency of >99.8 %. Additionally, the rate performance demonstrated that this electrolyte is capable of passing current density as high as 7mA/cm<sup>2</sup> without any electrolytic decomposition and offers a superior capacity retention. We have also demonstrated an ‘anode free’ LFP-Cu cell which was cycled over 50 cycles and achieved an average coulombic efficiency of 98.74%. The coordination chemistry and (electro)chemical understanding as well as the excellent cycling stability collectively leads toward a breakthrough in realizing the practical applicability of this ether aided ionic liquid electrolytes in lithium metal battery applications, while delivering high energy density in a prototype cell.


Ionics ◽  
2019 ◽  
Vol 25 (9) ◽  
pp. 4351-4360 ◽  
Author(s):  
Zhongliang Yu ◽  
Jiahe Zhang ◽  
Chunxian Xing ◽  
Lei Hu ◽  
Lili Wang ◽  
...  

RSC Advances ◽  
2020 ◽  
Vol 10 (34) ◽  
pp. 20173-20183
Author(s):  
Yasai Wang ◽  
Guilin Feng ◽  
Yang Wang ◽  
Zhenguo Wu ◽  
Yanxiao Chen ◽  
...  

Lithium–sulfur batteries are considered to be promising energy storage devices owing to their high energy density, relatively low price and abundant resources.


2020 ◽  
Vol 12 (23) ◽  
pp. 25853-25860 ◽  
Author(s):  
Yu-Ting Kao ◽  
Shivaraj B. Patil ◽  
Chi-Yao An ◽  
Shao-Ku Huang ◽  
Jou-Chun Lin ◽  
...  

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