Quasi-Solid Aluminum-Ion Electrolyte for Capacity and Cycle Stability
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Solution Overview
Problem
Aluminum-ion secondary batteries (AIBs) with non-aqueous electrolytes, particularly with oxidic cathodes, suffer from low capacities, low cell voltages, and low cycle stability.
Innovation Solution
The use of an aluminum secondary battery comprising a cathode with oxidic or carbon-based materials, an anode with aluminum or aluminum alloys, and an electrolyte made of room temperature ionic liquids (RTILs) and deep eutectic solvents (DESs) containing bivalent metal cations, which enhances ion conductivity and mobility, and includes a quasi-solid electrolyte with a high proportion of aluminum salts for improved capacity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-aqueous electrolytes (RTILs and DESs) are used in aluminum-ion secondary batteries, then aluminum deposition is enabled, but the batteries still suffer from low capacities, low cell voltages, and low cycle stability
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing bivalent metal cations (Cu2+, Zn2+, Ni2+) into the RTIL/DES system. This parameter change enables the electrolyte to simultaneously achieve high ion conductivity for aluminum deposition and provide additional redox reactions that increase capacity and voltage, while the bivalent metal cations form stable complexes that improve cycle stability
Solution Approach 2:
The patent creates a composite electrolyte system combining RTIL or DES with bivalent metal salts (such as CuCl2, ZnCl2, NiCl2). This composite approach integrates the advantages of RTIL/DES (enabling aluminum deposition) with the benefits of bivalent metal cations (enhancing capacity, voltage, and stability through additional redox couples and stable complex formation)
2Reliability
If aluminum salts are dissolved in the electrolyte to enable aluminum deposition, then aluminum ion conductivity is achieved, but the aluminum cannot be deposited if the salt is kept too strongly in solution
Solution Approach 1:
The bivalent metal cations act as intermediaries that form stable complexes with aluminum ions and the electrolyte components. These complexes serve as intermediate species that facilitate aluminum deposition by controlling the solvation shell and reducing the strength of aluminum-ion solvation, enabling aluminum to be deposited while maintaining adequate ion conductivity
Solution Approach 2:
The patent modifies the electrolyte composition parameters by adding bivalent metal salts that change the solvation chemistry. This parameter change adjusts the balance between aluminum-ion solvation strength and ion mobility, creating optimal conditions for both maintaining ion conductivity and enabling aluminum deposition
3Quantity of substance
If the electrolyte ensures high ion conductivity and mobility at operating temperature, then the battery achieves good performance, but the electrolyte contributes to high resistance
Solution Approach 1:
The bivalent metal cations provide continuous useful action through multiple redox couples (Al3+/Al, Cu2+/Cu, Zn2+/Zn, Ni2+/Ni) that can sequentially participate in charge and discharge reactions. This continuity maintains high ion conductivity and reduces resistance by providing multiple parallel ion transport and electron transfer pathways throughout the battery operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in increased capacitances, cell voltages, and cycle stability, eliminating the need for a separator and reducing the risk of short-circuits, while providing safer and more efficient energy storage.
Implementation Method 1
The electrolyte must also ensure high ion conductivity and mobility at operating temperature (e.g., room temperature) so that the electrolyte does not contribute to the battery with a high resistance
Implementation Method 2
In addition, the electrolyte has to reversibly coat the negative aluminum electrode without dendrites forming
Implementation Method 3
Carbon-based cathodes for AIBs are known from the literature, such as graphite or graphene. These cathodes enable reversible intercalation/deintercalation of AlCl4− complexes during charging/discharging
Implementation Method 4
electrochemical energy storage with rechargeable batteries (secondary batteries) plays a major role
Data Source
AI summary
The invention relates to an aluminum secondary battery comprising at least one positive electrode, at least one negative electrode, at least one electrolyte, and at least one additive, the electrolyte comprising at least one room temperature ionic liquid (RTIL), made of at least one organic salt and at least one first aluminum salt, and/or at least one deep eutectic solvent (DES) made of at least one organic solvent and at least one first aluminum salt, the additive containing bivalent metal cations and/or being suitable for forming bivalent metal cations.