Weak Cation–Solvent Interactions in Ether‐Based Electrolytes Stabilizing Potassium‐ion Batteries

Abstract

Conventional ether-based electrolytes exhibited a low polarization voltage in potassium-ion batteries, yet suffered from ion-solvent co-intercalation phenomena in a graphite anode, inferior potassiummetal performance, and limited oxidation stability.Here, we reveal that weakening the cation-solvent interactions could suppress the co-intercalation behaviour, enhance the potassium-metal performance, and improve the oxidation stability. Consequently, the graphite anode exhibits K + intercalation behaviour (K j j graphite cell operates 200 cycles with 86.6 % capacity retention), the potassium metal shows highly stable plating/stripping (K j j Cu cell delivers 550 cycles with average Coulombic efficiency of 98.9 %) and dendritefree (symmetric K j j K cell operates over 1400 hours) properties, and the electrolyte exhibits high oxidation stability up to 4.4 V. The ion-solvent interaction tuning strategy provides a promising method to develop highperformance electrolytes and beyond.

Less is More: Trace Amount of a Cyclic Sulfate Electrolyte Additive Enable Ultra-Stable Graphite Anode for High-Performance Potassium-Ion Batteries

“…At a current density of 50 mA g –1 , the full-cell could deliver a high initial capacity of 108 mA h g –1 with a capacity retention of 80.5% after 100 cycles, and the average Coulombic efficiency is as high as 99.7% (Figure c). This result is comparable to the best performances among all reported PTCDA–graphite PIB full-cells using the concentrated electrolyte or artificial SEI film, as listed in Table S4. ,,− The full-cell delivers a superior rate capability of the full-cell. The capacities are 115.1, 100.8, 96.6, 91.1, and 87.6 mA h g –1 at current densities of 20, 40, 60, 80, and 100 mA g –1 , respectively (Figure d).…”

Cyclic-anion salt for high-voltage stable potassium-metal batteries

“…Though the PF 6 − anion could passivate Al collector, the PF 6 − anion-based electrolytes usually suffer from poor cycle stability and low coulombic efficiency (CE), stemming from their insufficient passivation ability on the anode surface and inferior oxidation-resistant properties [ 25–27 ]. The bis(fluorosulfonyl)imide (FSI − ) anion-based electrolytes generally can form an efficient passivation layer on the anode surface [ 28 – 31 ], but will cause corrosion on the Al collector [ 23 , 32 ] possibly due to the impurities in FSI-based salts [ 33 ]. It also has been reported that the FSI − anion could passivate Al foil effectively at certain voltages, yet corrode stainless steel components [ 34 ].…”

Bismuth nanoparticles embedded in a carbon skeleton as an anode for high power density potassium-ion batteries

“…It is well known that the electrochemical performance of electrode materials is closely related to the type of electrolyte. [49][50][51][52] Therefore, two types of electrolytes (1 M KPF 6 in diethylene glycol dimethyl ether (DEGDME) and 0.8 M KPF 6 in ethylenecarbonate (EC)/diethyl-carbonate (DEC)) are selected rst to study the cycling performance and the selected charge/ discharge curves of Bi@C composites (Fig. S4 †).…”