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.

Advancements in cathode materials for potassium-ion batteries: current landscape, obstacles, and prospects

“…Ever since the discovery of reversible electrochemical K + insertion/extraction in graphite, a plethora of electrolytes have been subjected to thorough investigation to unveil their physicochemical properties. 36,54,383,[395][396][397][398][399] To date, an array of electrolyte systems has been extensively studied, encompassing organic-solvent-based electrolytes, ionic liquid electrolytes, aqueous electrolytes, and solid-state electrolytes. Notably, research endeavours have predominantly concentrated on organic liquid electrolytes.…”

Restructuring Electrolyte Solvation by a Partially and Weakly Solvating Cosolvent toward High-Performance Potassium-Ion Batteries

“…18,19 To address this problem with lowconcentration electrolytes (LCEs), several strategies have been proposed regarding the development of high-performance electrolytes, including high-concentration electrolytes (HCEs), 20,21 localized HCEs (LHCEs), 22 and weakly solvating electrolytes (WSEs). 23,24 These electrolytes preferentially coordinate anions with cations to form contact ion pairs (CIPs) and aggregated ion pairs (AGGs) in bulk electrolytes, which produce a strong inorganic passivation layer on the electrode surface. 25 HCEs, despite their potential benefits, are hindered from commercial deployment due to their prohibitive costs and elevated viscosity.…”

Bifunctional Alloy/Solid-Electrolyte Interphase Layer for Enhanced Potassium Metal Batteries Via Prepassivation

“…Unsatisfactorily, the incompatibility and complexity of such operations on the environmentally sensitive K metal may eventually deteriorate the fragile interface. Because the extraneous components in the artificial SEI layer are susceptible and cannot deliver self-healing properties when corrupted, it is almost unattainable to fabricate chemically and/or mechanically stable layers for K metal with dense and homogeneous properties. − Although the incompatibility may be solved by solvating sheath regulation (employing novel solvents and additives) for the natural SEI layer, , this fails in the modifications of CC and artificial SEI layer. Thus, the development of an off-the-shelf approach in interface engineering is imperative to construct affinity substrate and a compatible SEI layer simultaneously, which is deemed as a more valid route to suppress K dendrite growth and side reaction.…”