A Nonflammable Electrolyte Enabled High Performance K<sub>0.5</sub>MnO<sub>2</sub> Cathode for Low-Cost Potassium-Ion Batteries

Deng, Leqing; Wang, Tianshuai; Hong, Youran; Feng, Meiying; Wang, Ruiting; Zhang, Juan; Zhang, Qianfan; Wang, Jiangwei; Zeng, Liang; Zhu, Yujie; Guo, Lin

doi:10.1021/acsenergylett.0c00912

Cited by 85 publications

(78 citation statements)

References 34 publications

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“…[18] In our previous work, a fire-retardant electrolyte using triethyl phosphate as its single solvent was reported to show much better performance on graphite than the conventional ethylene carbonate (EC) and diethyl carbonate (DEC) electrolyte, and this electrolyte can also work on a K 0.5 MnO 2 cathode with over 4 V charging potential. [19,20] This is a good sign that nonflammable electrolyte can be adopted to address the safety of PIBs, although no nonflammable electrolyte has achieved long-term calendar performance in graphite anode for PIBs so far. The success or failure of an electrolyte is normally attributed to the stability of the SEI.…”

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confidence: 99%

Manipulating the Solvation Structure of Nonflammable Electrolyte and Interface to Enable Unprecedented Stability of Graphite Anodes beyond 2 Years for Safe Potassium‐Ion Batteries

et al. 2020

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redox potential of K + is close to that of Li + but lower than for Na +. [1-4] Another important motivation for PIB research is that K + cations can be reversibly intercalated into the commercial graphite anode used for LIBs with a high theoretical capacity of 279 mAh g −1 based, on the generated compound KC 8 , which offers the encouraging prospect of PIBs suitable for high manufacturability, by using the commercial production lines for LIBs. [5-7] For the large-scale applications of PIBs, long-term calendar life and high safety are the most two critical factors. The graphite anode in PIBs, however, suffers from poor stability due to the continual decomposition of the electrolyte and insufficient solid electrolyte interphase (SEI) protection. [8] The electrolyte plays a vital role in determining the performance of electrode materials and regulating the SEI to eliminate interfacial side reactions and ensure long-term cyclability and high safety. Tremendous efforts have been made to regulate electrolytes by altering the salts, solvents, additives, and/ or concentrations. [9,10] In the case of the salt for PIBs, the most attractive one is potassium bis(fluorosulfonyl)imide (KFSI), as it could lead to a more stable SEI than is possible with other salts, such as KPF 6 and potassium bis(trifluoromethanesulfonyl) imide. [11-14] Also, it has been demonstrated that the stability of graphite can be enhanced by simply increasing the salt concentration in conventional carbonate or ether-based electrolytes. An electrolyte consisting of KFSI and ethyl methyl carbonate (EMC) at the high molar ratio of 1:2.5 made the graphite anode work for 17 months. Benefiting from the robust inorganic-rich SEI layer generated by the concentrated KFSI with EMC, this long cycle-life performance of graphite is the best that has ever been achieved in reported electrolytes. [15] The carbonate or ether-based electrolytes are highly combustible and volatile, however, which poses a great potential hazard for accidents involving explosion and fire. Although the volatility and flammability can be reduced in highly concentrated electrolytes, safety still remains an issue, especially for large-scale implementation. [16,17] It is well known that the flammability of the electrolyte is mainly determined by the property of solvents, and thus, there are also efforts toward developing nonflammable electrolytes Potassium-ion batteries (PIBs) are attractive for low-cost and large-scale energy storage applications, in which graphite is one of the most promising anodes. However, the large size and the high activity of K + ions and the highly catalytic surface of graphite largely prevent the development of safe and compatible electrolytes. Here, a nonflammable, moderate-concentration electrolyte is reported that is highly compatible with graphite anodes and that consists of fire-retardant trimethyl phosphate (TMP) and potassium bis(fluorosulfonyl)imide (KFSI) in a salt/solvent molar ratio of 3:8. It shows unprecedented stability, as evidenced by its 74% capacity r...

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Manipulating the Solvation Structure of Nonflammable Electrolyte and Interface to Enable Unprecedented Stability of Graphite Anodes beyond 2 Years for Safe Potassium‐Ion Batteries

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“…Guo and co‐workers [ 34 ] found that in KFSI–TEP electrolyte, K metal anode could achieve a stable plating/stripping with a small voltage hysteresis and a high average coulombic efficiency of 99.6% during 500 cycles. Guo and co‐workers [ 35 ] also confirmed that the average coulombic efficiency of K 0.5 MnO 2 (4.0 vs K + /K) in KFSI–TEP electrolyte could achieve more than 99.6% and retain 84% capacity even after 400 cycles. Moreover, compared with the EC/DEC electrolyte, the K 0.5 MnO 2 in TEP electrolyte could remain the original bulk structure during cycling process.…”

Section: Nonaqueous Electrolyte For Potassium‐ion Batteriesmentioning

confidence: 86%

The Features and Progress of Electrolyte for Potassium Ion Batteries

Liu

Gao

Dai

et al. 2020

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Nowadays, Li‐ion batteries have achieved great success and are widely used in various fields. However, the scarcity and uneven distribution of lithium resources together with the increasing cost may hamper the sustainable development of Li‐ion batteries in the future. Hence, many researchers have turned to potassium ion batteries due to their abundant raw materials, low price, and high energy density. Although great progress has been made in recent years, there are still existing many challenges, especially the severe side reaction between electrolyte and K metal, which leads to an unstable solid–liquid interface and low coulombic efficiency. Hence, an excellent electrolyte may be the key to development of K‐ion batteries in the future. Unfortunately, no systematic research has been conducted to study the electrolyte and its role on the performance yet. In order to compensate for this limitation, in this paper, the status and progress of electrolytes for K‐ion batteries are reviewed, the issues and challenges existing in the development of electrolyte are clarified, and the future development is prospected.

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“…replaced the flammable EC with fire‐retardant TEP in the potassium bis(fluorosulfonyl) imide (KFSI) salt‐based electrolyte, which not only improved the battery safety, but also eliminated the exfoliation of layered K 0.5 MnO 2 cathode caused by EC solvent co‐intercalation. [ 79 ] A graphite||K 0.5 MnO 2 full cell based on the optimized electrolyte delivered superior long‐term cycle performance with an average Coulombic efficiency of ≈99.81%. Liu et al.…”

Section: Non‐flammable Organic Liquid Electrolytesmentioning

confidence: 99%

Non‐Flammable Liquid and Quasi‐Solid Electrolytes toward Highly‐Safe Alkali Metal‐Based Batteries

Jaumaux

Shanmukaraj

et al. 2020

Adv Funct Materials

172

133

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Rechargeable alkali metal (i.e., lithium, sodium, potassium)‐based batteries are considered as vital energy storage technologies in modern society. However, the traditional liquid electrolytes applied in alkali metal‐based batteries mainly consist of thermally unstable salts and highly flammable organic solvents, which trigger numerous accidents related to fire, explosion, and leakage of toxic chemicals. Therefore, exploring non‐flammable electrolytes is of paramount importance for achieving safe batteries. Although replacing traditional liquid electrolytes with all‐solid‐state electrolytes is the ultimate way to solve the above safety issues, developing non‐flammable liquid electrolytes can more directly fulfill the current needs considering the low ionic conductivities and inferior interfacial properties of existing all‐solid‐state electrolytes. Moreover, the electrolyte leakage concern can be further resolved by gelling non‐flammable liquid electrolytes to obtain quasi‐solid electrolytes. Herein, a comprehensive review of the latest progress in emerging non‐flammable liquid electrolytes, including non‐flammable organic liquid electrolytes, aqueous electrolytes, and deep eutectic solvent‐based electrolytes is provided, and systematically introduce their flame‐retardant mechanisms and electrochemical behaviors in alkali metal‐based batteries. Then, the gelation techniques for preparing quasi‐solid electrolytes are also summarized. Finally, the remaining challenges and future perspectives are presented. It is anticipated that this review will promote a safety improvement of alkali metal‐based batteries.

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A Nonflammable Electrolyte Enabled High Performance K_0.5MnO₂ Cathode for Low-Cost Potassium-Ion Batteries

Cited by 85 publications

References 34 publications

Manipulating the Solvation Structure of Nonflammable Electrolyte and Interface to Enable Unprecedented Stability of Graphite Anodes beyond 2 Years for Safe Potassium‐Ion Batteries

Manipulating the Solvation Structure of Nonflammable Electrolyte and Interface to Enable Unprecedented Stability of Graphite Anodes beyond 2 Years for Safe Potassium‐Ion Batteries

The Features and Progress of Electrolyte for Potassium Ion Batteries

Non‐Flammable Liquid and Quasi‐Solid Electrolytes toward Highly‐Safe Alkali Metal‐Based Batteries

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A Nonflammable Electrolyte Enabled High Performance K0.5MnO2 Cathode for Low-Cost Potassium-Ion Batteries

Cited by 85 publications

References 34 publications

Manipulating the Solvation Structure of Nonflammable Electrolyte and Interface to Enable Unprecedented Stability of Graphite Anodes beyond 2 Years for Safe Potassium‐Ion Batteries

Manipulating the Solvation Structure of Nonflammable Electrolyte and Interface to Enable Unprecedented Stability of Graphite Anodes beyond 2 Years for Safe Potassium‐Ion Batteries

The Features and Progress of Electrolyte for Potassium Ion Batteries

Non‐Flammable Liquid and Quasi‐Solid Electrolytes toward Highly‐Safe Alkali Metal‐Based Batteries

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A Nonflammable Electrolyte Enabled High Performance K_0.5MnO₂ Cathode for Low-Cost Potassium-Ion Batteries