Amine-Wetting-Enabled Dendrite-Free Potassium Metal Anode.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Potassium metal batteries are promising for grid-scale storage due to potassium's low cost and abundance.
• Challenges include potassium dendrite growth, volume changes, and unstable solid electrolyte interphase (SEI) on the anode.
• Existing conductive scaffolds often result in non-uniform composites with compromised capacity.

Purpose of the Study:

• To develop a dendrite-free, practical potassium composite anode using amine-functionalized carbon scaffolds.
• To enhance potassium metal anode performance by improving wetting and accommodating volume fluctuations.
• To enable stable solid electrolyte interphase (SEI) formation for long-cycle life.

Main Methods:

• Amine functionalization of carbon scaffolds to create potassiophilic surfaces.
• Facile and rapid infusion of molten potassium into functionalized carbon scaffolds.
• Experimental characterization and theoretical calculations to understand potassium interaction with amine groups.
• Fabrication and testing of a full cell using the K@CC anode and a K_0.7Mn_0.7Ni_0.3O₂ cathode.

Main Results:

• Amine functionalization transformed carbon scaffolds from non-wetting to potassium-wetting, enabling fast molten potassium infusion.
• The carbon-cloth-based potassium composite anode (K@CC) effectively accommodated volume changes and reduced local current density.
• Nondendritic potassium morphology and a stable SEI were achieved.
• The K_0.7Mn_0.7Ni_0.3O₂|K@CC full cell demonstrated excellent rate capability and over 8000 cycles with 68.5% capacity retention at 1 A g^-1.

Conclusions:

• Amine functionalization is an efficient strategy for fabricating high-performance potassium composite anodes.
• The K@CC anode effectively suppresses dendrite formation and enhances cycling stability.
• This approach offers a viable pathway for practical and durable potassium metal batteries for grid-scale energy storage.