Building an artificial solid electrolyte interphase on spinel lithium manganate for high performance aqueous lithium-ion batteries

Abstract

Spinel lithium manganate (LiMn₂O₄) is a promising cathode for aqueous lithium-ion batteries (ALIBs). However, due to Mn dissolution and the Jahn–Teller effect it suffers from fast capacity fading, insufficient rate capability, and low overcharge resistance. Herein, a ∼2–3 nm artificial solid electrolyte interphase (SEI) layer (lithium polyacrylate, LiPAA) is constructed on the commercial LiMn₂O₄ (LiPAA@LiMn₂O₄). It is realized by an in situ polymerization hydrothermal reaction using an acrylic monomer. This artificial SEI layer can separate the electrode and aqueous electrolyte, thus suppressing Mn dissolution and the Jahn–Teller effect of LiMn₂O₄. Electrochemical analyses also suggest it may work as the Li⁺ conductor/reservoir to improve the Li⁺ diffusion coefficient of the electrode. Consequently, as the cathode of ALIBs, LiPAA@LiMn₂O₄ harvests a high capacity of 119 mA h g⁻¹ at 0.6C, high rate capability (70 mA h g⁻¹ at 12C), better durability (85.5%@100 cycles) and superior overcharge resistance.