Moderate Specific Surface Areas Help Three-Dimensional Frameworks Achieve Dendrite-Free Potassium-Metal Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium (K) metal anodes are crucial for next-generation batteries but are hindered by dendrite growth.
• Three-dimensional frameworks with potassiophilic coatings can mitigate dendrite formation by increasing surface area and reducing current density.

Purpose of the Study:

• To investigate the impact of electrochemically active surface area (ECSA) on potassium deposition behavior.
• To develop a dendrite-free potassium metal anode using tin disulfide (SnS2) nanosheets on a carbon paper framework (SnS2@CP).

Main Methods:

• Synthesized SnS2 nanosheets of varying sizes and loaded them onto carbon paper (CP) to create SnS2@CP frameworks.
• Evaluated the relationship between SnS2 nanosheet size, ECSA, specific surface area, and potassium deposition behavior.
• Tested the electrochemical performance of the SnS2@CP anodes, including nucleation overpotential and cycle life.

Main Results:

• The size of SnS2 nanosheets dictates the ECSA of the framework, which correlates with specific surface area.
• Optimal ECSA and specific surface area led to uniform potassium electrodeposition with a low nucleation overpotential of 11.2 mV.
• The SnS2@CP anode demonstrated a cycle life exceeding 800 hours at 0.25 mA cm⁻².

Conclusions:

• Tuning the ECSA through controlled SnS2 nanosheet size is a viable strategy for stable potassium metal anodes.
• The developed SnS2@CP framework offers a promising solution for safe and efficient potassium metal batteries.