A Four-Electron-Transfer Robust Small-Molecule Organic Anode for Low-Strain Potassium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-ion batteries (PIBs) are crucial for large-scale energy storage due to abundant potassium resources.
• Developing high-capacity and durable anodes for PIBs is challenging due to the large K+ ion radius.
• Existing anode materials often struggle with stability and limited potassium ion accommodation.

Purpose of the Study:

• To introduce a novel small-molecule organic compound, 2,2 -bipyridine-4,4 -dicarboxylic acid (BDA), as a high-performance anode for PIBs.
• To investigate the electrochemical properties, structural stability, and K+ storage mechanism of BDA.
• To demonstrate the potential of BDA in all-organic PIBs.

Main Methods:

• Electrochemical testing (galvanostatic cycling, rate capability)
• In situ/ex situ characterization techniques
• Theoretical calculations (e.g., DFT)

Main Results:

• BDA exhibits a high reversible capacity of 398 mAh g^-1 at 100 mA g^-1.
• Excellent cycling stability with 186 mAh g^-1 retained after 1000 cycles at 1000 mA g^-1.
• An all-organic PIB with a BDA anode achieved an energy density of 174 Wh kg^-1.

Conclusions:

• BDA demonstrates significant potential as a stable, high-capacity organic anode for PIBs.
• The K+ storage mechanism involves reversible redox activity at carbonyl and imine sites with minimal volume fluctuation.
• This work paves the way for advanced organic electrode materials in next-generation energy storage systems.