Engineering of Electrode-Electrolyte Interphase for High Performance Aqueous Rechargeable Batteries

Abstract

The development of advanced aqueous rechargeable batteries is critical for the realization of sustainable, safe, and cost-effective energy storage systems to support renewable energy technologies. However, challenges such as narrow electrochemical stability windows and material degradation limit their practical application potential. To address these issues, this thesis systematically introduces electrode-electrolyte interphases for aqueous lithium-ion, aqueous sodium-ion and aqueous zinc-ion batteries to enhance their electrochemical performance. In the first study, a novel hybrid electrolyte system comprising lithium methanesulfonate-trimethyl phosphate (LiMS-TMP-H2O) was developed to address key limitations of aqueous batteries, including the narrow electrochemical stability window (ESW) and low output voltage. The in-situ formation of lithium phosphate interphases (Li3PO4), derived from TMP, significantly enhances the ESW to approximately 4.5 V, enabling compatibility with a wide range of electrode pair materials. These include LiMn2O4(LMO)/LiTi2(PO4)3 (LTP), LMO/TiO2, LMO/Li4Ti5O12(LTO), LMO/Zn2Nb34O87(ZnNbO), LiCoO2(LCO)/LTO, LiN0.33Co0.33Mn0.33O2(NCM111)/LTO, and LiNi0.5Co0.2Mn0.3O2(NCM523)/LTO. These configurations exhibit high output voltages (up to 2.5 V) and excellent cycling stability, with performance maintained over 1,000 cycles. Notably, this electrolyte design offers an exceptionally low bill of materials (BOM) cost, accounting for only 0.4% of the cost of a 21 m water-in-salt (WIS) electrolyte and approaching the cost of dilute aqueous sulfate electrolytes. These attributes highlight the potential of this electrolyte as a universal and cost-effective solution for the development of high-voltage, long-lifespan aqueous batteries. The second study elucidates the phase transformation mechanism of NaMnO2 and introduces TMP as a multifunctional electrolyte co-solvent for aqueous sodium-ion batteries. TMP not only enhances sodium-ion intercalation/de-intercalation on the cathode side but meanwhile in-situ forms a stable, robust and uniform solid electrolyte interphase on the anode side. These functions lead to batteries with enhanced performance with a high specific capacity of 198.21 mAh/g, an operation time of over 1440h and an energy density of 121.935 Wh/kg and in addition, this co-solvent expands the electrochemical stability window of the electrolyte to around 3.0V and imparts excellent low-temperature performance to the batteries (82.91mAh/g at -20℃), advancing ASIBs as a safe and environmentally friendly energy storage solution. In the third study, the challenges of cathode degradation in Zn/MnO2 batteries are addressed through the development of an artificial Kaolinite-based Cathode-Electrolyte Interphase (K-CEI). This interphase effectively mitigates Mn2+ dissolution and suppresses the formation of Zn-vernadite nanoplates, ensuring stable cathode morphology and improved cyclic stability. The batteries with K-CEI achieve a reversible specific capacity of 380.89 mAh/g over 1,000 cycles and maintain superior performance across various MnO2 phases, providing insights into the design of next-generation long-lifespan aqueous Zn/MnO2 batteries.