Lithium-Ion Cathode Material with Repeated Lithiation for Low Capacity Loss
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Solution Overview
Problem
Current delithiating materials for lithium ion batteries have low purity and low dilithiation capacity, making them unsuitable for fully addressing lithium ion loss issues in lithium ion batteries, and their preparation methods are complex and difficult to industrialize.
Innovation Solution
A delithiating material with the chemical formula Li(9x+2y+z)MnyMezO(3y+z)N2xX3x is developed, where x, y, and z are optimized within specific ranges, and a multi-stage sintering process is used to enhance lithium ion conductivity and stability, involving chemical co-precipitation, heat treatment, and repeated sintering with lithium powder and halide to achieve high dilithiation capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If simple preparation methods are used for delithiating materials, then manufacturing complexity is reduced, but the purity and dilithiation capacity of the material are low
Solution Approach 1:
The preparation process is divided into multiple sequential stages: chemical co-precipitation to form precursor, first heat treatment to obtain intermediate product, and repeated sintering cycles with lithium powder and halide. Each stage produces a material with progressively higher purity and controlled composition, resolving the contradiction between process simplicity and material quality.
Solution Approach 2:
The chemical co-precipitation step performs preliminary purification and composition control before heat treatment. By pre-forming the precursor with controlled stoichiometry and purity, subsequent processing steps become simpler while maintaining high final material quality, addressing the contradiction between ease of manufacture and manufacturing precision.
2Reliability
If multi-stage sintering process is used to improve dilithiation capacity, then lithium ion conductivity increases, but manufacturing complexity increases
Solution Approach 1:
The repeated sintering cycles with lithium powder and halide perform continuous lithium incorporation and phase optimization. Each cycle builds upon the previous one, progressively enhancing lithium ion conductivity and dilithiation capacity while maintaining a systematic and repeatable process framework, balancing reliability improvement with manageable complexity.
Solution Approach 2:
The multi-stage sintering process systematically varies critical parameters including temperature (e.g., 600-900°C ranges), holding time, and lithium halide composition across different cycles. These controlled parameter changes enable progressive optimization of material properties, achieving high lithium ion conductivity through systematic parameter evolution rather than complex process design.
3Use of energy by moving object
If high lithium capacity cathode material is used to improve energy density, then battery energy density increases, but initial coulombic efficiency decreases due to SEI film formation
Solution Approach 1:
The delithiating material acts as an intermediary lithium source between the cathode and anode. It provides excess lithium ions that compensate for SEI film formation losses, enabling high capacity cathode materials to achieve their full potential while maintaining high initial coulombic efficiency. The intermediary material decouples the contradiction between energy density and coulombic efficiency.
Solution Approach 2:
The delithiating material is designed to be partially consumed during initial cycles, with excess lithium intentionally discarded to form SEI film. This controlled discarding of lithium from the delithiating material protects the main cathode lithium reservoir, allowing high energy density cathode materials to operate at their full capacity in subsequent cycles with high coulombic efficiency.
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 resulting delithiating material exhibits high dilithiation capacity, stable performance, and easy storage, with initial capacities exceeding 400 mAh/g and reduced capacity loss, effectively addressing the limitations of prior materials.
Implementation Method 1
a material with a high lithium capacity to the cathode... excess lithium element is extracted from the high lithium capacity cathode material and inserted into the anode to compensate the irreversible lithium capacity loss
Implementation Method 2
a multi-stage sintering process is used to enhance lithium ion conductivity and stability, involving chemical co-precipitation, heat treatment, and repeated sintering
Data Source
AI summary
The present invention discloses a lithium ion battery with low capacity loss, which comprises an cathode material, a anode material and an electrolyte. The cathode material has a chemical formula Li(9x+2y+z)MnyMezO(3y+z)N2xX3x (xLi9N2X3·yLi2MnO3·zA), and has advantages such as stable performance, low surface residue, and high dilithiation capacity. The preparation of the cathode material comprises the steps of: synthesis of a precursor from a metal salt and a manganese compound by chemical co-precipitation, followed by, sequentially, heat treatment and crushing; and repeated lithium supplementation and multi-stage sintering to form the cathode material. The method for preparing the cathode material is simple. By repeated lithium supplementation and sintering, Li3N is inserted into the lattice of the material. Li9N2X3 forms a eutectic with the base material, which further reduces the surface residue, improves the storage and cycling performance of the material. The components complement each other and coexist synergistically, and the prepared cathode material has the advantages of high dilithiation capacity and low capacity loss.