Solid-State Battery Cathode Additive for Lithium Compensation
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Solution Overview
Problem
Conventional secondary batteries, particularly those with organic solvent-based cells, face limitations in stability and energy density, while all-solid-state batteries using inorganic solid electrolytes offer improved safety and simplicity but require a sacrificial cathode material to conserve lithium ions during charging and discharging.
Innovation Solution
A cathode for all-solid-state batteries incorporating a sacrificial additive with a perovskite crystal structure, represented by (La2/3-xLi3x□1/3-2x)TiO3, where □ is a vacant site for charge neutrality, and x satisfies 0.04≤x≤1/6, which also exhibits lithium ion conductivity of at least 1×10−3 S/cm and electron conductivity of 1×10−8 to 1×10−2 S/cm, formed through a multi-step calcination process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sacrificial cathode material is used to conserve lithium ions during initial charging and discharging, then lithium ion stability is improved, but the cathode requires additional materials and increased complexity
Solution Approach 1:
The patent combines the sacrificial cathode material function with the cathode active material itself. The cathode active material is designed to undergo redox reactions at potentials lower than its discharge voltage during initial charging, serving both as the energy-storing material and the sacrificial material that conserves lithium ions. This eliminates the need for separate sacrificial cathode materials and reduces cathode structure complexity.
Solution Approach 2:
The cathode active material is given multiple functions: it serves as both the energy-storing cathode material and the sacrificial material for lithium ion conservation during initial cycles. This multi-functionality approach eliminates the need for additional dedicated sacrificial materials, thereby reducing device complexity while maintaining lithium ion stability.
2Ease of manufacture
If conventional organic solvent-based cells are used, then ease of manufacture is improved, but stability and energy density are limited
Solution Approach 1:
The patent changes the fundamental parameter of the electrolyte from organic solvent-based to inorganic solid electrolyte. This parameter change enables the battery to achieve improved stability and energy density while maintaining manufacturability through established solid-state battery manufacturing processes. The inorganic solid electrolyte allows for safer operation and higher energy density without requiring complex manufacturing changes.
3Reliability
If inorganic solid electrolyte is used to improve safety and simplify structure, then reliability is improved, but additional sacrificial cathode material is required
Solution Approach 1:
The patent merges the function of the inorganic solid electrolyte with the cathode active material by designing the cathode material to perform sacrificial redox reactions. This combination eliminates the need for separate sacrificial cathode materials that would otherwise be required when using inorganic solid electrolytes, thereby maintaining safety and simplicity while reducing cathode material complexity.
Solution Approach 2:
The cathode active material is designed to serve multiple functions: energy storage and sacrificial lithium ion conservation. This multi-functionality is particularly important when using inorganic solid electrolytes, as it eliminates the need for additional dedicated sacrificial materials, thereby maintaining the simplicity and safety benefits of solid-state batteries while reducing overall device complexity.
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
The additive enhances lithium ion and electron migration within the cathode, improving charge and discharge capacities and efficiencies of all-solid-state batteries without the need for additional conductive materials, thereby addressing the limitations of conventional batteries.
Implementation Method 1
The sacrificial cathode material is used in redox reactions at a potential lower than the discharge voltage of a cathode active material in the initial charging stage, and emits lithium ions.
Implementation Method 2
an all-solid-state battery using an inorganic solid electrolyte is manufactured based on technology in which any organic solvent is excluded
Implementation Method 3
preparing an additive represented by Formula 1 below by tertiarily calcining a resultant product obtained from the secondary calcining at a temperature higher than a temperature of the secondary calcining
Data Source
AI summary
A cathode for all-solid-state batteries includes an additive as a sacrificial cathode material, and a method for manufacturing cathode for all-solid-state batteries. The additive may include a compound represented by Formula 1 below,(La2/3-xLi3x□1/3-2x)TiO3, [Formula 1]wherein □ may indicate a vacant site for achieving charge neutrality depending on a doping amount of lithium, and x may satisfy an equation of 0.04≤x≤⅙.