Building an artificial solid electrolyte interphase on spinel lithium manganate for high performance aqueous...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Spinel lithium manganate (LiMn2O4) is a potential cathode material for aqueous lithium-ion batteries (ALIBs).
• LiMn2O4 faces challenges including manganese dissolution, Jahn-Teller effect, capacity fading, poor rate capability, and low overcharge resistance.

Purpose of the Study:

• To enhance the performance of LiMn2O4 cathodes in ALIBs.
• To suppress manganese dissolution and the Jahn-Teller effect in LiMn2O4.
• To improve the electrochemical properties of LiMn2O4 for ALIB applications.

Main Methods:

• Constructed a ∼2-3 nm artificial solid electrolyte interphase (SEI) layer of lithium polyacrylate (LiPAA) on commercial LiMn2O4 (LiPAA@LiMn2O4).
• Utilized an in situ polymerization hydrothermal reaction with an acrylic monomer to form the LiPAA SEI layer.
• Conducted electrochemical analyses to evaluate the performance of the modified electrode.

Main Results:

• The LiPAA SEI layer effectively separated the electrode from the aqueous electrolyte, suppressing Mn dissolution and the Jahn-Teller effect.
• Electrochemical analyses indicated the LiPAA layer may act as a Li+ conductor/reservoir, enhancing the Li+ diffusion coefficient.
• LiPAA@LiMn2O4 demonstrated a high capacity (119 mA h g-1 at 0.6C), excellent rate capability (70 mA h g-1 at 12C), improved durability (85.5% capacity retention after 100 cycles), and superior overcharge resistance.

Conclusions:

• The artificial SEI layer significantly improves the electrochemical performance of LiMn2O4 cathodes in ALIBs.
• LiPAA@LiMn2O4 offers a promising solution for developing high-performance and stable aqueous lithium-ion batteries.
• The developed method provides a viable strategy for modifying cathode materials to overcome performance limitations in aqueous battery systems.