Air-Stable High-Voltage Li-Ion Organic Cathode Enabled by Localized High-Concentration Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Lithium-ion batteries rely on critical minerals, posing supply chain risks.
• Organic cathodes offer a sustainable alternative to traditional metal-based cathodes.
• Dithiin-fused dilithium naphthazarin (DNP-Li) is explored as a high-voltage organic cathode material.

Purpose of the Study:

• To evaluate the performance of DNP-Li as a Li-ion organic cathode.
• To investigate the impact of localized high-concentration electrolyte (LHCE) on DNP-Li's electrochemical behavior.
• To understand solute-electrolyte interactions in multielectron small-molecule organic cathodes.

Main Methods:

• Electrochemical performance testing of DNP-Li with different electrolytes (carbonate-based vs. LHCE).
• Analysis of voltage profiles and phase transitions under varying electrolyte conditions.
• Cycling stability assessment at different charge/discharge rates (0.1C and 0.5C).

Main Results:

• DNP-Li demonstrates high operating potential (3.55 V vs. Li+/Li) and specific capacity (232 mAh g-1).
• LHCE significantly improves cycling stability, retaining 85% capacity after 50 cycles at 0.1C and 75% after 160 cycles at 0.5C.
• Electrolyte composition dictates voltage profiles and phase transition reversibility.

Conclusions:

• DNP-Li is a promising, stable, high-voltage organic cathode material.
• LHCE enhances DNP-Li performance by reducing redox intermediate solubility and improving cycling stability.
• Solute-electrolyte interactions are crucial for optimizing multielectron organic cathode performance for sustainable energy storage.