Rationally Engineered Two-Phase Heterostructured Carbons with a Desired Operating Voltage for High-Performance...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-ion batteries (PIBs) face challenges with anode materials lacking high capacity, safe operating voltages, and rapid ion transport.
• Existing carbon anodes suffer from issues like hazardous plating or compromised energy density.

Purpose of the Study:

• To develop a new anode material for PIBs that simultaneously achieves high capacity, safe voltage, and fast ion transport.
• To overcome the limitations of traditional hard carbon anodes in PIBs.

Main Methods:

• Engineered a two-phase heterostructured carbon (THC) material with a gradient graphitic degree via phase engineering.
• Utilized a post-coating and pyrolysis process to create the unique heterostructure.
• Investigated the synergistic effects of intercalation and pore-filling mechanisms.

Main Results:

• The THC anode exhibits a reversible capacity of ~400 mA h g⁻¹ at 50 mA g⁻¹ and an average operating potential of 0.54 V (vs K⁺/K).
• Achieved exceptional rate capability, retaining >150 mA h g⁻¹ at 1000 mA g⁻¹, with a high initial Coulombic efficiency of 61%.
• Successfully prevented hazardous ultralow-voltage plating and avoided compromised energy density.

Conclusions:

• The developed THC material significantly outperforms existing carbon-based anodes for PIBs.
• This novel heterostructure offers a promising solution for advanced potassium-ion battery development.