Mitigating Voltage Decay and Enhancing Structural Stability of Li-Rich Cathodes via a Robust Polysaccharide Binding...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Li-rich layered manganese-based oxides (LRMOs) are promising high-capacity cathode materials for next-generation lithium-ion batteries (LIBs).
• Commercialization is hindered by capacity fading, voltage decay, structural instability, and electrolyte decomposition.
• Transition-metal dissolution from LRMOs further exacerbates performance degradation.

Purpose of the Study:

• To develop a robust multifunctional binding network for LRMO cathodes.
• To address mechanical and interfacial challenges limiting LRMO performance and stability.
• To explore a sustainable, water-processable binder strategy for advanced LIBs.

Main Methods:

• A composite binder was engineered using guar gum (GG) and xanthan gum (XG) polysaccharides.
• The XG-GG binder formed a hydrogen-bonded network to enhance mechanical strength and adhesion.
• The binder's polar functional groups were utilized to form a protective cathode electrolyte interphase (CEI) and adsorb dissolved transition-metal ions.

Main Results:

• The XG-GG binder demonstrated superior mechanical strength and adhesion compared to conventional poly(vinylidene difluoride) (PVDF).
• LRMO cathodes with XG-GG exhibited enhanced electrochemical performance, including a high initial capacity (266.3 mAh/g) and improved capacity retention (84.2% after 100 cycles).
• The binder effectively suppressed electrode cracking, active material loss, and transition-metal dissolution, leading to suppressed average voltage decay.

Conclusions:

• The XG-GG composite binder establishes a robust, multifunctional network that synergistically overcomes mechanical and interfacial issues in LRMO cathodes.
• This water-based binder strategy offers a sustainable and effective approach for improving the long-term stability and electrochemical performance of high-energy LIBs.
• The findings pave the way for practical application of LRMOs in next-generation energy storage devices.