Solvation Structure Modulation of High-Voltage Electrolyte for High-Performance K-Based Dual-Graphite Battery

Area of Science:

• Energy Storage
• Materials Science
• Electrochemistry

Background:

• Potassium-based dual-carbon batteries (K-DCBs) offer promising energy storage due to abundant resources.
• Conventional electrolytes in K-DCBs suffer from poor oxidation resistance and limited anion intercalation at high voltages, hindering performance.
• Novel electrolyte systems are crucial for advancing K-DCB technology.

Purpose of the Study:

• To address the limitations of conventional electrolytes in K-DCBs.
• To develop an effective strategy for improving both potassium ion (K+) storage and anion (bis(fluorosulfonyl)imide, FSI-) intercalation.
• To demonstrate a high-performance K-DCB through electrolyte optimization.

Main Methods:

• A solvation structure modulation strategy was employed for the K-DCB electrolyte.
• The strategy focused on optimizing the interaction between electrolyte components and electrode materials.
• Performance was evaluated through electrochemical testing of a proof-of-concept K-DCB.

Main Results:

• The solvation modulation strategy significantly improved K+ ion storage at the graphite anode.
• Enhanced bis(fluorosulfonyl)imide anion (FSI-) intercalation capacity was achieved at the graphite cathode.
• The assembled K-DCB demonstrated a discharge capacity of 103.4 mAh g-1 with approximately 90% capacity retention after 400 cycles.
• The full cell achieved an energy density of 157.6 Wh kg-1, setting a new benchmark for K-DCBs.

Conclusions:

• Solvation structure modulation is an effective strategy for enhancing K-DCB performance.
• The developed electrolyte system overcomes limitations of conventional electrolytes, enabling superior ion and anion intercalation.
• This work paves the way for high-performance and stable potassium-based energy storage devices.