Additives Capable of Stably Supplying Anions/Cations for Homogeneous Lithium Deposition/Stripping

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium dendrite formation is a major challenge in lithium battery safety and performance, caused by slow ion transport and uneven Li+ distribution.
• Existing electrolyte additives often struggle to effectively regulate lithium deposition and SEI formation.

Purpose of the Study:

• To develop a functional electrolyte additive, P35, to regulate lithium deposition and suppress dendrite growth.
• To investigate the mechanism by which P35 enhances lithium-ion transport and promotes uniform plating.

Main Methods:

• Synthesis of a novel copolymer P35 with a quaternary ammonium group (N3R+I-).
• Theoretical calculations to elucidate the interaction between P35, lithium ions, and electrolyte components.
• Electrochemical testing of Li-Li symmetric and Li-LiFePO4 full cells with and without P35 additive.

Main Results:

• P35 preferentially adsorbs on the lithium anode surface, hindering lithium salt anion adsorption and improving Li+ transport.
• P35 facilitates the formation of a more stable solid electrolyte interphase (SEI) through a dual charge electrostatic shield.
• Cells with P35 exhibit enhanced rate performance, reduced polarization, and smoother lithium deposition morphology.

Conclusions:

• P35 effectively regulates lithium deposition by optimizing ion transport and SEI formation, leading to improved battery performance.
• The P35 additive presents a promising strategy for developing safer and more efficient lithium-based batteries.