Over-Lithiated Ceramic Solid Electrolyte for Higher Battery Capacity
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Solution Overview
Problem
Current lithium-ion batteries face limitations in energy capacity and number of charge/discharge cycles, particularly in applications requiring high performance, safety, and reduced size and weight, which solid-state batteries aim to address but still need improvements in energy density and service life.
Innovation Solution
A method for producing an over-lithiated ceramic solid electrolyte by increasing the lithium concentration beyond the stoichiometric ratio, achieved through immersion in molten lithium, mixing with lithium powder, or vapor deposition, to enhance lithium ion conductivity and provide additional lithium for the anode formation during the first charging cycle, allowing for a smaller cathode and reduced material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the cathode is dimensioned to provide sufficient lithium for anode formation, then the battery achieves adequate capacity, but the battery weight and material usage increase
Solution Approach 1:
The solid electrolyte is pre-lithiated during manufacturing to store excess lithium before battery operation. This preliminary action ensures that lithium is already available in the electrolyte to form the anode during the first charging cycle, eliminating the need to oversize the cathode with additional lithium reserves.
Solution Approach 2:
The solid electrolyte acts as an intermediary lithium reservoir between the cathode and anode. By storing excess lithium within the electrolyte structure itself, it mediates the lithium transfer process, allowing the cathode to be smaller while still providing sufficient lithium for anode formation through the electrolyte's stored lithium.
2Reliability
If a liquid electrolyte is used in lithium-ion batteries, then ion transport is enabled, but cooling circuits are required which increase size and weight
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid ceramic form. This parameter change eliminates the need for cooling circuits while maintaining lithium ion conductivity, thereby reducing battery size and weight without sacrificing ion transport capability.
Solution Approach 2:
The cooling circuit system is extracted and removed from the battery design by using a solid electrolyte that does not require thermal management. This extraction eliminates the associated volume and weight while preserving the essential ion transport function.
3Power
If prelithiation is performed to increase power density, then energy capacity improves, but irreversible losses during cycling increase
Solution Approach 1:
The solid electrolyte is pre-lithiated during manufacturing to store excess lithium that compensates for irreversible losses during cycling. This preliminary action ensures that even after initial capacity losses, sufficient lithium remains available to maintain power density throughout the battery's operational life.
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 approach increases the energy density and service life of solid-state batteries by enabling a higher lithium capacity, reducing weight and material costs, and minimizing lithium depletion risks, while compensating for lithium losses through side reactions.
Implementation Method 1
over-lithiating the ceramic solid electrolyte, wherein a lithium concentration in the ceramic solid electrolyte is increased beyond the stoichiometric lithium concentration of the ceramic
Implementation Method 2
They can achieve significantly more charging cycles, do not self-decompose or overheat and offer a more homogeneous power distribution
Data Source
Figure 1~2
AI summary
The invention relates to a method for producing a solid electrolyte for use in a solid-state battery, the method comprising the following steps: - producing a ceramic solid electrolyte with the stoichiometric ratio specific to the ceramic, - over-lithiating the ceramic solid electrolyte, whereby the lithium concentration in the ceramic solid electrolyte is increased beyond the stoichiometric lithium concentration of the ceramic. The invention further relates to a solid electrolyte which has been over-lithiated by such a method.