| 1. |
- Park, Jimin, et al.
(författare)
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Regulating the Solvation Structure of Electrolyte via Dual–Salt Combination for Stable Potassium Metal Batteries
- 2023
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Ingår i: Advanced Science. - 2198-3844 .- 2198-3844. ; 10:16
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Tidskriftsartikel (refereegranskat)abstract
- Batteries using potassium metal (K-metal) anode are considered a new type of low-cost and high-energy storage device. However, the thermodynamic instability of the K-metal anode in organic electrolyte solutions causes uncontrolled dendritic growth and parasitic reactions, leading to rapid capacity loss and low Coulombic efficiency of K-metal batteries. Herein, an advanced electrolyte comprising 1 M potassium bis(fluorosulfonyl)imide (KFSI) + 0.05 M potassium hexafluorophosphate (KPF6) dissolved in dimethoxyethane (DME) is introduced as a simple and effective strategy of regulated solvation chemistry, showing an enhanced interfacial stability of the K-metal anode. Incorporating 0.05 M KPF6 into the 1 M KFSI in DME electrolyte solution decreases the number of solvent molecules surrounding the K ion and simultaneously leads to facile K+ de-solvation. During the electrodeposition process, these unique features can lower the exchange current density between the electrolyte and K-metal anode, thereby improving the uniformity of K electrodeposition, as well as potentially suppressing dendritic growth. Even under a high current density of 4 mA cm−2, the K-metal anode in 0.05 M KPF6-containing electrolyte ensures high areal capacity and an unprecedented lifespan with stable Coulombic efficiency in both symmetrical half-cells and full-cells employing a sulfurized polyacrylonitrile cathode.
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| 2. |
- Park, Jimin, et al.
(författare)
-
Stable Solid Electrolyte Interphase for Long-Life Potassium Metal Batteries
- 2022
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 7:1, s. 401-409
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Tidskriftsartikel (refereegranskat)abstract
- Potassium (K) is considered to be the most suitable anode material for rechargeable K batteries because of its high theoretical capacity (686 mAh g(-1)) and low redox potential (-2.93 V vs SHE). However, uneven electrodeposition of K during cycling usually leads to the growth of dendrites, resulting in low Coulombic efficiency and compromising battery safety. Herein, we develop a strategy for stabilizing K metal through simple interface control. The conductive passivation layer can be controllably designed by a spontaneous chemical reaction when a K metal foil is kept in contact with a liquid-phase potassium-polysulfide (PPS); this guides the formation of an electronically and ionically conductive solid electrolyte interphase layer including K2S compound, enabling dense K plating with a dendrite-free morphology. Compared to the bare K metal anode, the PPS-treated K metal anode demonstrates superior cycling stability in symmetric half cells and full cells using a TiS2 cathode under practical constraints.
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