Layered Positive Electrode Material for High-Voltage Cycle Stability
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Solution Overview
Problem
Conventional lithium-ion battery positive electrodes coated with oxides or fluorides experience reduced performance due to by-products under high-voltage conditions, affecting lithium ion passage and cycle life.
Innovation Solution
A positive electrode material with a layered structure containing strip-like structures and atom clusters, incorporating elements like Y or Ca between layers, enhances aggregation density and stability, reducing side reactions and improving cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional oxide or fluoride coating is applied to the positive electrode surface, then contact between electrolyte and positive electrode material is reduced, but passage of lithium ions is hindered, adversely affecting battery performance
Solution Approach 1:
The patent applies different elements (M1: Y or Ca; M2: La, Ho, Zr, Sc, W, Ce, Mo, Nb, Hf, Zn, or Ti) at specific locations within the layered structure - M1 between layers and M2 in atom clusters within strip-like structures. This local differentiation creates regions with distinct properties: some areas reduce electrolyte contact while others facilitate lithium ion passage, resolving the contradiction between protection and conductivity.
Solution Approach 2:
The patent creates a composite layered structure combining multiple elements (M1 and M2) with the base positive electrode material. This composite approach integrates the protective function of oxide/fluoride coatings with the ion-conducting properties of the base material, achieving both reduced electrolyte contact and maintained lithium ion passage through the synergistic combination of different materials.
2Power
If high-voltage working conditions are used to increase energy density, then power output is improved, but by-products are generated on the positive electrode surface, affecting cycle performance
Solution Approach 1:
The patent incorporates elements M1 and M2 in advance within the layered structure before the battery operates under high-voltage conditions. These pre-positioned elements act as protective agents that prevent the formation of harmful by-products during high-voltage operation, counteracting the degradation effects before they can occur. This preliminary protection maintains cycle performance while enabling high-voltage operation for improved energy density.
Solution Approach 2:
The patent transforms the high-voltage condition, which normally generates harmful by-products, into a beneficial operating state. By incorporating elements M1 and M2 in the layered structure, the high-voltage operation is converted into a condition that activates the protective functions of these elements, which stabilize the crystal structure and prevent by-product formation, thereby converting what would be a harmful condition into a beneficial one for maintaining cycle performance.
Data Source
AI summary
A positive electrode material, an electrochemical device that uses same, and an electronic device. Specifically, a positive is a layered structure. The layered structure includes a strip-like structure containing an atom cluster. The positive electrode material according to this application helps to improve cycle performance and storage performance of the electrochemical device under a high voltage working condition.