Lithium-Ion Cathode Material with Crack-Induced Prelithiation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing prelithiating materials for lithium ion batteries suffer from low purity, high impurity content, and poor reproducibility due to agglomeration and segregation during synthesis, limiting the utilization of cathode materials and reducing battery capacity.
Innovation Solution
A prelithiating material with a chemical formula LiNi(1-x)MeXO, where x is 10−6 to 10−1, and Me is a third metal, is prepared through a method involving chemical co-precipitation, calcination, inducing treatment to create cracks, and sintering with Li2O, using inducing environments and chemicals to enhance purity and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solid-phase synthesis methods are used to prepare Li2NiO2, then the material can be synthesized, but the purity is low due to agglomeration and segregation of NiO during the synthesis process
Solution Approach 1:
The synthesis process is divided into multiple sequential steps: chemical co-precipitation to form precursor, calcination to form NiO, inducing treatment to create crack structure, and final sintering with Li2O. This segmentation prevents agglomeration and segregation by controlling each step independently, achieving high purity Li2NiO2 with 97.6% purity as demonstrated in the patent.
Solution Approach 2:
The inducing treatment is performed before the final sintering step to pre-create a crack structure in the NiO precursor. This preliminary action ensures that during the subsequent sintering process, lithium ions can effectively penetrate and react with NiO, preventing segregation and improving purity of the final product.
2Quantity of substance
If high-capacity silicon anode materials are used to improve energy density, then specific capacity increases, but volume expansion and low initial coulombic efficiency limit practical application
Solution Approach 1:
The prelithiating material Li2NiO2 serves a dual function: it acts as the cathode material for the battery while simultaneously serving as an external lithium source to compensate for lithium consumption during SEI formation. This self-service approach resolves the contradiction by making the cathode material contribute to solving the anode's coulombic efficiency problem.
Solution Approach 2:
The invention recovers lithium ions from the Li2NiO2 cathode material during charging and redistributes them to the anode during discharge, effectively recovering the lithium consumed by SEI formation. This allows the high-capacity silicon anode to be practically utilized despite initial lithium consumption.
3Quantity of substance
If existing prelithiating materials with small particle sizes are used to compensate lithium loss, then lithium supplementation capacity increases, but storage becomes difficult due to high activity
Solution Approach 1:
The inducing treatment creates a localized crack structure within the particles of Li2NiO2, concentrating the reactive sites at specific locations rather than throughout the entire particle. This local quality improvement maintains high lithium supplementation capacity while the overall particle structure remains stable for storage, resolving the contradiction between activity and storability.
4Manufacturing precision
If multiple-step sintering processes are used to prepare lithium supplementing additives, then material formation is achieved, but the process becomes complicated and difficult to reproduce
Solution Approach 1:
The chemical co-precipitation step preliminarily forms a uniform precursor structure that contains both nickel and the third metal element in precise stoichiometric ratios. This preliminary action ensures that subsequent calcination and sintering steps proceed smoothly with good reproducibility, reducing overall process complexity while maintaining material formation quality.
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 method produces a prelithiating material with high purity and delithiation capacity, improving the overall electric capacity of lithium ion batteries by enhancing lithium ion reaction efficiency and reducing segregation.
Implementation Method 1
subjecting precursor 2 to an inducing treatment to induce a crack structure
Implementation Method 2
the inducing effect of the inducing environment or the inducing chemical, the crystal structure is changed
Implementation Method 3
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 4
mixing precursor 3 with Li2O in an equimolar ratio, sintering in an inert atmosphere, and crushing to prepare the prelithiating material
Implementation Method 5
sintering in an inert atmosphere
Data Source
AI summary
The present invention discloses a lithium ion battery with high capacity, which comprises an cathode material, a anode material and an electrolyte. The cathode material has a chemical formula LiNi(1-x)MexO, wherein x is 10−6 to 10−1, and Me is a third metal other than Li and Ni. Said material has the advantages of high purity, high density and high delithiation capacity. The preparation method of the cathode material comprises: subjecting a nickel salt and an additive to chemical co-precipitation, calcining, and inducing of a crack structure with an inducing environment, an inducing chemical, or a combination thereof to give a precursor, which is mixed with Li2O, sintered and crushed to give the cathode material. Through the inducing effect of the inducing environment or the inducing chemical, the crystal structure is changed, cracks are formed, and the volume of the crystal cell is further enlarged, so that lithium ions can react with NiO more sufficiently, thereby reducing the segregation, improving the purity and density of the prelithiating material, improving the delithiation capacity, and improving the overall electric capacity of the lithium ion battery.