Interphases in the electrodes of potassium ion batteries

Abstract

Rechargeable potassium-ion batteries (PIBs) are of great interest as a sustainable, environmentally friendly, and cost-effective energy storage technology. The electrochemical performance of a PIB is closely related to the reaction kinetics of active materials, ionic/electronic transport, and the structural/electrochemical stability of cell components. Alongside the great effort devoted in discovering and optimising electrode materials, recent research unambiguously demonstrates the decisive role of the interphases that interconnect adjacent components in a PIB. Knowledge of interphases is currently less comprehensive and satisfactory compared to that of electrode materials, and therefore, understanding the interphases is crucial to facilitate electrode materials design and advance battery performance. The present review aims to summarise the critical interphases that dominate the overall battery performance of PIBs, which includes solid-electrolyte interphase (SEI), cathode-electrolyte interphase (CEI), and solid-solid interphases in composite electrodes, via exploring their formation principles, chemical compositions, and determination of reaction kinetics. State-of-the-art design strategies of robust interphases are discussed and analysed. Finally, perspectives are given to stimulate new ideas and open questions to further the understanding of interphases and the development of PIBs.

Impact of Milling Conditions on Hard and Soft Carbon Properties and Performance in Potassium-Ion Batteries

“…Furthermore, the formulation of the slurry comprising binder and additive type − as well as its preparation process, play crucial roles in maintaining the initial carbon properties and enhancing the electrode performance, thereby improving ICE. Additionally, the choice of salt, solvent, and additives in the electrolyte impacts the stability of SEI layer, affecting the ICE. − Calendaring of electrodes, both for half and full cells, is also fundamental in achieving better ICE . In the case of full cells, the ICE can be influenced by the mass ratio between positive and negative electrodes as well as their respective working potentials.…”

Diglyme-Based Gel Polymer Electrolytes for K-Ion Capacitors

“…The large peaks observed in both electrodes, before and after cycling, for the de-convoluted high-resolution F 1s spectra (around 689-688 eV) represent the CF species originating from the PVDF binder [48]. An increase in the concentration of KF species (684-685 eV) was observed in the F1s of both KICs after cycling, indicating the decomposition of the potassium salt (KPF 6 → KF + PF 5 ) or its hydrolysis (KPF 6 + H 2 O (trace) → KF + 2HF + OPF 3 ) in presence of trace amount of water [48,49]. On the other hand, while considering the high-resolution P 2p spectra (Figs.…”

2023 roadmap for potassium-ion batteries

“…As the bridge to connect anode and cathode, the electrolyte is crucial in affecting the PIBs performance in terms of rate capability, lifespan, reversible capacity, and safety. This is controlled by the stability and properties of the SEI and cathode electrolyte interphase (CEI) at the anode and cathode, resulting from the degradation of the solvent and/or salt during the battery cycling process [213]. Although extensively studied and well characterized in LIBs, the SEI/CEI components for PIBs are ambiguous and remain one of the most critical fields for future research.…”