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

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.