Low-Moisture Positive Electrode Material for Solid-State Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing batteries suffer from low initial charge and discharge efficiency due to trace amounts of water, hydrated water, and hydroxyl groups in the active material, which cause side reactions with the solid electrolyte.
Innovation Solution
The positive electrode material is composed of a complex oxide represented by LiNi x Me 1-x O 2, where x satisfies 0.5 ≤ x ≤ 1, and Me is Mn, Co, or Al, with a water content of 317.5 ppm by mass or less, and a halide solid electrolyte, which is dried under specified conditions to minimize water content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active material is used with conventional water content, then the battery can be manufactured easily, but the initial charge and discharge efficiency is low due to side reactions with solid electrolyte
Solution Approach 1:
The active material undergoes preliminary drying treatment at 100°C for 1 hour before battery assembly to remove water and prevent side reactions during initial charging, thereby improving initial charge and discharge efficiency without complicating the manufacturing process
Solution Approach 2:
The water content of the active material is controlled to be 317.5 ppm by mass or less through drying treatment, changing the physical parameter of moisture content to prevent harmful side reactions with the solid electrolyte and improve battery efficiency
2Reliability
If water content in active material is reduced to 317.5 ppm or less, then initial charge and discharge efficiency is improved, but additional drying treatment is required
Solution Approach 1:
Drying treatment is performed as a preliminary step before battery assembly to remove water from the active material, ensuring low water content (317.5 ppm or less) is achieved before the material contacts the solid electrolyte, thereby improving efficiency while keeping the process simple
Solution Approach 2:
The active material is dried in a straightforward manner at 100°C for 1 hour, allowing the material itself to undergo the necessary water removal treatment without requiring complex equipment or multiple processing steps
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
This configuration results in a battery with improved initial charge and discharge efficiency by preventing electrolyte deterioration and maintaining high conductivity, reducing resistance, and enhancing charge and discharge characteristics.
Implementation Method 1
when an active material is manufactured, treatment for significantly reducing the amount of water in the active material and hydrated water, hydroxyl groups, and so on originated from the water is necessary and proceeded with further research. As a result, it was possible to find that when an active material is manufactured, water, hydrated water, hydroxyl groups, etc. contained in the active material can be greatly reduced by performing drying under specified conditions.
Implementation Method 2
trace amounts of water, hydrated water, hydroxyl groups, etc. contained in an active material cause side reactions with a solid electrolyte to decrease the initial efficiency
Data Source
Figure 1
AI summary
The positive electrode active material of the present disclosure includes a complex oxide represented by a formula (1): LiNixMe1-xO2 as a main component and contains water generated during heating at 300°C in Karl Fischer titration in an amount of 317.5 ppm by mass or less. Here, x satisfies 0.5 ≤ x ≤ 1, and Me is at least one element selected from the group consisting of Mn, Co, and Al.