Crosslinked Hetero-Chain Polymeric Interphase Enables the Stable Cycling of Li-Rich Mn-Based Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium-rich manganese-based layered oxides (LRMO) offer high energy density but suffer from electrolyte consumption and capacity decay.
• Existing cathode electrolyte interphase (CEI) strategies are insufficient for LRMO's unique structural demands.

Purpose of the Study:

• To identify specific CEI requirements for LRMO cathodes.
• To design a novel CEI strategy to enhance LRMO battery performance and stability.

Main Methods:

• Development of a non-fluorinated additive, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane (TVTMS).
• Formation of a crosslinked hetero-chain polymeric CEI (CHP-CEI) via ring-opening polymerization and ethylene crosslinking.
• Utilizing single-particle aerosol mass spectrometry (SPAMS) to analyze CEI components.

Main Results:

• The novel CHP-CEI demonstrates superior robustness, flexibility, and energy dissipation compared to conventional additives.
• Effective mitigation of LRMO cathode cracking, gas evolution, and transition metal dissolution.
• Achieved >825 cycles with 204 mAh g⁻¹ remaining capacity in Li|LRMO cells.
• High-loading cathodes (12 mg cm⁻²) maintained 80% capacity over >145 cycles.

Conclusions:

• The designed CHP-CEI effectively addresses LRMO cathode limitations, enhancing cycle life and stability.
• TVTMS offers a promising solution for next-generation high-energy density batteries.
• The study demonstrates the utility of SPAMS for CEI component analysis.