Polymer-Shelled Lithium Additive for Stable First-Cycle Replenishment
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Solution Overview
Problem
Existing lithium-replenishing additives for lithium-ion batteries are unstable, easily react with water and carbon dioxide, and require strict environmental conditions, leading to reduced battery capacity and difficulty in industrial production.
Innovation Solution
A lithium-replenishing additive with a lithium-rich-material core coated by a polymer layer and optionally an electrochemically active layer, where the core is doped with elements like Cu, Co, Al, Ti, V, Zr, or Fe to enhance stability and a shell layer to isolate the core from air, improving lithium replenishment efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an existing lithium-replenishing additive is used to compensate for lithium loss during first charging, then the lithium-replenishing effect is improved, but the additive reacts with water and carbon dioxide in air, resulting in high residual alkali content and reduced battery capacity
Solution Approach 1:
A polymer coating layer is applied on the surface of the lithium-replenishing additive particles to form a protective shell. This shell physically isolates the reactive lithium-rich core material from contact with water and carbon dioxide in the air, preventing the formation of residual alkali while maintaining the lithium-replenishing capability during battery operation.
Solution Approach 2:
The additive is designed as a composite structure consisting of a lithium-rich core material (such as Li2SiO3, Li3PO4, or Li4SiO4) encapsulated by a polymer matrix. This composite structure combines the high lithium content of the core material with the protective and stabilizing properties of the polymer shell, achieving both effective lithium replenishment and environmental stability.
2Reliability
If an existing lithium-replenishing additive is used to improve first efficiency, then lithium loss is compensated, but the additive requires extremely strict environmental requirements during use and storage
Solution Approach 1:
The polymer coating layer serves as a barrier that protects the lithium-rich core material from environmental factors during storage and handling. This allows the additive to be stored and transported under normal conditions without requiring strict environmental controls, while still maintaining its effectiveness in replenishing lithium during battery operation.
Solution Approach 2:
The polymer shell provides self-protection functionality, automatically preventing unwanted reactions with environmental factors without requiring external protective measures or strict environmental monitoring during storage and handling.
3Reliability
If an existing lithium-replenishing additive is used to replenish lithium, then capacity loss is compensated, but the additive is easy to be oxidized and difficult to be synthesized in quantity
Solution Approach 1:
The composite structure with polymer encapsulation protects the lithium-rich core material from oxidation during the synthesis process and storage. This enables scalable production through conventional ceramic synthesis methods followed by polymer coating, making large-scale manufacturing feasible while maintaining the capacity replenishment effect.
Solution Approach 2:
The polymer coating is applied to the lithium-rich particles before they are introduced into the battery, pre-protecting them from oxidation during synthesis, storage, and handling. This preliminary protective action enables straightforward synthesis procedures and facilitates industrial-scale production.
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 effectively replenishes lithium, enhances battery efficiency, and ensures stability during production, storage, and transportation, facilitating industrial production and improving battery performance.
Implementation Method 1
The shell layer includes a polymer layer... The polymer layer can effectively isolate air, such that the stability of the lithium-replenishing additive is further improved
Implementation Method 2
A doping element M can relieve a reaction of lithium and nickel with air, such that the lithium-replenishing additive is inhibited from forming a residual alkali
Data Source
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AI summary
A lithium-replenishing additive is provided in the present disclosure. The lithium-replenishing additive includes a lithium-rich-material core and a shell layer disposed at the lithium-rich-material core. The lithium-rich-material core is made of a lithium-rich material with an average chemical formula of aNixMyOz·bLi2O, where 0.95≤x≤1, 0.01≤y≤0.05,1≤z≤1.15, 0.8≤a≤1.1, 0.8≤b≤1.1, and the M includes one or more of copper (Cu), cobalt (Co), aluminum (Al), titanium (Ti), vanadium (V), zirconium (Zr), or iron (Fe). The shell layer includes a polymer layer. The lithium-replenishing additive not only can effectively replenish a lithium secondary battery with lithium to improve a first efficiency of a battery, but also can have good stability to be not easy to react in air, which is beneficial to production, storage, and transportation of the lithium-replenishing additive. A preparing method of a lithium-replenishing additive is further provided in the present disclosure.