Spatially Selective Solvation Chemistry by Local Charge Enrichment for Stable Potassium-Metal Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium metal batteries (PMBs) face challenges from dendrite growth and unstable electrode-electrolyte interfaces.
• These issues limit the practical application and cycle life of PMBs.

Purpose of the Study:

• To design a functional intermediate medium for stabilizing the interface in PMBs.
• To improve potassium ion (K+) deposition and overall battery performance.

Main Methods:

• Synthesized molybdenum carbide decorated N-doped carbon (MoC/NC) as a functional intermediate medium.
• Investigated the interaction between MoC/NC and KFSI electrolyte molecules.
• Fabricated and tested MoC/NC@K electrodes in symmetric and full cells.

Main Results:

• The MoC/NC medium induced a stable solid electrolyte interphase (SEI) layer rich in inorganic components like KF.
• The SEI layer suppressed electron tunneling, while MoC/NC facilitated balanced K+ and electron diffusion.
• Symmetric cells achieved stable cycling over 800 hours at 0.5 mA cm-2, with enhanced performance in full cells.

Conclusions:

• The MoC/NC functional intermediate medium effectively regulates interface chemistry in PMBs.
• This multi-scale strategy enhances interfacial transport kinetics and promotes uniform potassium deposition.
• The study presents a novel approach for improving the stability and performance of potassium metal batteries.