Lithium-ion Batteries
The high cost and safety flaws of batteries are still present, while the usage is greatly increased. In this study, we aim to replace flammable organic electrolyte with highly concentrated aqueous electrolyte (water-in-salt, WiS) to make more sustainable and safer lithium-ion batteries (LIB). The challenge in water-based LIB is, however, the low electrochemical stability window of water. To prevent the water electrolysis inside batteries, we propose to build protective interlayers on battery electrodes (called solid-electrolyte interphase, SEI, layer). The challenges in thin film production will be tackled by using wet synthesis which is a cheap and easily tunable approach to form robust protective layers. The protective shell structure will, therefore, enable us to use a variety of anode and cathode pairs that can provide a high electrochemical potential difference, thereby increasing the cycle life and energy density of next-generation aqueous batteries.
Research Objective:
Our objective is to develop a recipe of conformal nanometer-thick layer synthesis on anode particles (TiO2) via a wet process that mimic naturally formed SEI in aqueous batteries. Our working hypothesis is that the nanometer thick conformal bilayer can be built through a layer-by-layer inorganic synthesis process. We will incorporate LiF nanoparticles on carbonaceous layer to achieve a similar composition of SEI layers observed in WiS batteries. The rationale to have carbonaceous inner layers and LiF outer layers are the easy formation of carbon layer on substrates and low conductivity (13.6 eV of bandgap and 10-31S/cm) and low water solubility of LiF. It is thus critical to evaluate the effect of this layer on aqueous battery performance to develop a robust synthesis method.