| With the large-scale development of global industry,environmental pollution and energy crisis issues have become increasingly serious.Therefore,it is urgent to develop high safety,low-cost,and high-efficiency green sustainable energy storage systems.Currently,lithium-ion battery（LIBs）technology is the most mature in the energy storage field.However,serious problems such as lithium resource shortages and flammability hinder the large-scale application of LIBs.Aluminum-ion batteries（AIBs）have aroused the research interest of scientific researchers due to their abundant global reserves,low flammability,low cost,and high energy density.This article focuses on the design and optimization of AIBs based on ionic liquid electrolytes.Trifluoromethanesulfonate aluminum（Al（OTF）3）or anhydrous aluminum chloride（AlCl3）is used as the aluminum ion source in the AIBs based on ionic liquid electrolyte,and the energy storage mechanism and electrochemical properties of AIBs based on ionic liquid electrolytes are studied.The main research results are as follows:（1）By mixing anhydrous AlCl3 and guanidinium hydrochloride（Gdn HCl）in different molar ratios,an AlCl3-Gdn HCl ionic liquid analog electrolyte for AIBs was prepared,and the effect of AlCl3 concentration on the electrochemical performance of the electrolyte was investigated,and aluminum storage mechanism of AlCl3-Gdn HCl electrolyte was studied.Using the aluminum-graphite batteries with AlCl3-Gdn HCl,excellent electrochemical performance was shown.At a current density of 1 A g-1,a discharge specific capacity of about 125 m A h g-1 was displayed with a high coulombic efficiency（CE）of nearly 99.5%;at 100 m A g-1,the discharge specific capacity was 128m A h g-1.Through electrochemical mechanism studies and material characterization analysis,it was proved that AlCl4-and Al2Cl7-anions existed in the AlCl3-Gdn HCl electrolyte,accompanied by an electrochemical mechanism of aluminum complex ion intercalation/deintercalation during charge and discharge,and it was confirmed that AlCl3-Gdn HCl electrolyte had highly reversible aluminum deposition/dissolution characteristics.（2）In the Al-S battery system,using an AlCl3/1-ethyl-3-methyl imidazolium chloride（[EMIm]Cl）ionic liquid electrolyte,the electrochemical performance of water-soluble cova1ently crosslinking c-QACES binder was studied.The c-QACES binder was prepared by mixing a quaternary ammonium salt（QACES）and succinic anhydride（SA）.At a current density of 200 m A g-1,the Al-S（c-QACES@S）battery featuring the c-QACES binder displayed excellent discharge specific capacity of 1452.1m A h g-1,and maintained a discharge specific capacity of 465.2 m A h g-1 after 100cycles,far surpassing prior literature results and thus greatly improving the low-capacity problem associated with Al-S batteries.Ex situ SEM characterization showed that the capture capacity and cyclic stability of c-QACES@S were significantly improved.The experiment results showed that the c-QACES binder is a low-cost design to solve the rapid capacity fading of Al-S cells,and provides a strategy for the development of high-performance environmental protection functionality binders for Al-S cells.（3）An Al salt quasi-solid-state electrolyte（Al-IGE）was developed for AIBs,which was prepared by dissolving PVDF-HFP and Al（OTF）3 in NMP solvent.Al-IGE exhibited polymer structure characteristics and could maintain its polymer structure without affecting it when Al（OTF）3 ions were introduced.Al-IGE is highly flexible,non-corrosive and environmentally friendly.At a current density of 200 m A g-1,the AIBs assembled with Al-IGE and Mn O2 cathode material showed an initial discharge specific capacity of 408.5 m A h g-1,and exhibited a normal working voltage under bending and cutting conditions.The Al-IGE can break through the limitation of traditional electrolyte and can be assembled in stainless steel button cells.The study of Al-IGE provides an effective solution for the design of high-performance flexible aluminum ion batteries with no corrosion effect. |
