A novel cathode interphase formation methodology by preferential adsorption of a borate-based electrolyte additive

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-energy-density batteries require stable interfaces between high-capacity cathodes and lithium metal anodes.
• Structural degradation of electrodes limits the practical application of advanced battery chemistries.
• Developing effective electrolyte additives is crucial for overcoming these stability challenges.

Purpose of the Study:

• To synthesize and evaluate tris(2,2,3,3,3-pentafluoropropyl) borane (TPFPB) as an electrolyte additive.
• To improve the stability of lithium metal anodes and Ni-rich layered oxide cathodes.
• To enhance the overall performance and cycle life of lithium-ion batteries.

Main Methods:

• Synthesis of TPFPB as an electrolyte additive.
• Electrochemical testing of Li metal||Ni-rich layered oxide full batteries with and without TPFPB.
• Analysis of cathode electrolyte interface (CEI) film formation and stability.
• Evaluation of battery performance under various conditions (high voltage, high mass loading, wide temperature range).

Main Results:

• TPFPB forms a stable (B and F)-rich CEI film on the cathode, suppressing side reactions.
• TPFPB enhances LiNO3 solubility by 30 times, improving Li metal anode stability.
• Batteries with TPFPB demonstrate ultralong cycle life (1500 cycles) and high stability.
• Exceptional performance achieved at 4.8 V, 30 mg cm⁻² mass loading, and -30 to 60°C.
• A 3.1 Ah pouch cell achieved 420 Wh kg⁻¹ energy density at 0.1 C.

Conclusions:

• TPFPB is a highly effective electrolyte additive for stabilizing lithium metal||Ni-rich layered oxide batteries.
• The additive significantly improves electrode interface stability, leading to enhanced cycling performance.
• TPFPB enables next-generation high-energy-density batteries with improved safety and durability.