Dual-Functional Additive Reshapes Lifetime Limit of Potassium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-ion batteries (PIBs) are a sustainable alternative to lithium-ion batteries.
• Irreversible potassium loss and unstable solid electrolyte interphase (SEI) formation limit PIB performance.
• Developing effective additives is crucial for advancing PIB technology.

Purpose of the Study:

• To identify a dual-functional additive for PIBs that enhances active potassium compensation and SEI stability.
• To improve the specific energy and cycling lifespan of PIBs.
• To provide mechanistic insights into additive function for future battery development.

Main Methods:

• Integrated computational-experimental selection framework for additive discovery.
• Electrochemical testing of coin-type and pouch-type full cells.
• Multimodal advanced characterizations and theoretical calculations for mechanistic studies.

Main Results:

• A novel dual-functional additive was identified, improving both potassium compensation and SEI stability.
• Additive-integrated cells demonstrated high specific energy (334.9 Wh kg⁻¹) and extended cycling lifespan (1700 cycles with 88.32% retention).
• Pouch-type cells maintained 80.64% capacity after 3000 cycles, validating the additive's effectiveness.

Conclusions:

• The additive effectively replenishes potassium ions and promotes a robust, inorganic-rich SEI.
• This dual action significantly enhances the electrochemical performance and durability of PIBs.
• The findings offer a new strategy for developing multifunctional additives for advanced energy storage systems.