Stabilized Lithiated Graphite Anode via Ex Situ Coating
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Solution Overview
Problem
Current lithium-ion battery designs face significant irreversible lithium loss during the first charging and discharging process due to irreversible reactions with anode materials, limiting the use of lithium-free cathode materials and requiring unsafe handling of metallic lithium powders for prelithiation, which is not commercially viable.
Innovation Solution
Partial or complete lithiation of graphite using a non-electrochemical process followed by stabilization with a coating to create a graphite-based anode material that is stable in air and reactive solvents, allowing safe handling and use in standard electrode production processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metallic lithium powder is added to compensate for irreversible lithium loss, then the electrochemical capacity is improved, but the safety and handling become problematic due to violent reactions with air and solvents
Solution Approach 1:
The patent introduces a coating layer as an intermediary substance between the metallic lithium powder and the external environment (air, solvents). This coating acts as a protective barrier that prevents direct contact and violent reactions, while still allowing the underlying lithium to fulfill its electrochemical function. The coating mediates the interaction between lithium and environment, enabling safe handling and processing.
Solution Approach 2:
The patent applies a protective coating to the lithium powder before it is exposed to air or solvents during electrode manufacturing. This preliminary protective action prevents the harmful violent reactions from occurring in the first place, rather than dealing with the consequences after reaction. The coating is applied in advance to counteract the inherent reactivity of lithium.
2Object-affected harmful factors
If stabilized lithium powder with coatings is used to improve safety, then the reactivity with solvents is reduced, but the stability is insufficient at elevated temperatures leading to runaway reactions
Solution Approach 1:
The patent employs a composite coating structure consisting of multiple layers with different functional properties. The coating is not a single material but a composite system where different layers provide different functions: one layer provides chemical stability and solvent resistance, while another layer provides thermal stability and prevents runaway reactions at elevated temperatures. This composite approach allows simultaneous improvement of both safety aspects.
3Ease of manufacture
If conventional electrode manufacturing methods are used with lithium-free graphite anodes, then the manufacturing process is simple and safe, but irreversible lithium loss occurs during initial charging limiting capacity
Solution Approach 1:
The patent merges two previously separate concepts: lithium-free graphite anodes (easy to manufacture) and metallic lithium powder (provides additional capacity). By combining lithiated graphite particles with metallic lithium powder in a composite anode structure, the patent achieves both manufacturing simplicity and enhanced electrochemical capacity. The merged system allows conventional manufacturing methods to be used while still benefiting from the capacity boost of additional lithium.
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 stabilized lithiated graphite anode material maintains high electrochemical capacity while being less reactive to air and solvents, enabling safe and efficient production and use in lithium-ion batteries, reducing lithium loss and improving handling safety.
Implementation Method 1
it is assumed that primarily oxygen-containing surface groups react irreversibly with lithium to form stable salts during the first battery charging process
Implementation Method 2
stabilization with a coating to create a graphite-based anode material that is stable in air and reactive solvents
Implementation Method 3
less reactive to air and solvents, enabling safe and efficient production
Implementation Method 4
liquid lithium, a temperature of 350°C is sufficient
Data Source
AI summary
Described is a coated, (partly) lithiated graphite powder characterized in that it has been produced in a non-electrochemical process from metallic lithium and graphite in powder form and has been stabilized outside an electrochemical cell by application of a coating layer; and a galvanic cell comprising a cathode, a lithium-conductive electrolyte-separator system and an anode comprising a coated, (partly) lithiated graphite powder, where the (partial) lithiation and the coating of the graphite powder are performed non-electrochemically outside the galvanic cell (ex situ).