All-Solid-State Cathode Structure for Electrolyte Contact Stability
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Solution Overview
Problem
Current all-solid-state batteries face challenges in achieving long-term life-cycle characteristics, high energy density, and high capacity due to limitations in suitable positive electrode active materials, which result in suboptimal performance and stability during charging and discharging.
Innovation Solution
A positive electrode for all-solid-state batteries is developed, comprising a lithium nickel-based composite oxide with secondary particles of radially arranged primary particles and a solid electrolyte, along with a conductive agent and binder, to enhance electrolyte penetration and connectivity, minimizing volume change and preventing separation between the active material and electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional positive electrode active materials are used in all-solid-state batteries, then the battery can be assembled with existing materials, but the battery fails to achieve satisfactory long-term life-cycle characteristics, high energy density, and high capacity
Solution Approach 1:
The patent changes the physical and chemical parameters of the positive electrode active material by controlling particle size (3-10 μm), morphology (radially arranged primary particles forming secondary particles), and composition (lithium nickel-based composite oxide with specific ratios of Ni, Co, Al, and Mn). These parameter changes enable the material to achieve both long-term life-cycle characteristics and high energy density in all-solid-state batteries.
Solution Approach 2:
The patent develops a composite positive electrode active material consisting of lithium nickel-based composite oxide with a specific composite structure where primary particles are radially arranged to form secondary particles. This composite structure combines the advantages of different materials to achieve high capacity, high energy density, and excellent life-cycle characteristics simultaneously.
2Reliability
If solid electrolyte is added to improve contact with positive electrode active material, then electrolyte penetration and connectivity are enhanced, but the structure becomes more complex
Solution Approach 1:
The patent utilizes the porous structure created by the radially arranged primary particles within secondary particles to facilitate solid electrolyte penetration. The radial arrangement creates interconnected void spaces that allow electrolyte to effectively contact the active material throughout the particle structure, enhancing connectivity without requiring additional complex structural elements.
3Productivity
If positive electrode active material undergoes repeated charging and discharging, then battery capacity is utilized, but volume change occurs causing separation between active material and solid electrolyte
Solution Approach 1:
The radial arrangement of primary particles within secondary particles creates a buffer structure that can accommodate volume changes during charging and discharging. The hierarchical structure allows for expansion and contraction without causing particle fracture or separation from the solid electrolyte, effectively cushioning the mechanical stress before it can cause damage.
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 solution results in an all-solid-state battery with improved energy density, capacity, efficiency, and extended life-cycle characteristics by facilitating better lithium diffusion and reducing stress during charge-discharge cycles.
Implementation Method 1
pressure transfer is facilitated to minimize or reduce a space between the particle components in the positive electrode, and a solid electrolyte can effectively penetrate between the positive electrode active materials
Implementation Method 2
a volume change of the positive electrode active material due to repeated charging and discharging is minimized or reduced
Data Source
AI summary
A positive electrode for an all-solid-state battery, a method of preparing the same, and an all-solid-state battery including the same are provided. The positive electrode for an all-solid-state battery includes a positive electrode active material including a first positive electrode active material including a lithium nickel-based composite oxide and being in a form of secondary particles in which a plurality of primary particles are aggregated and at least a portion of the primary particles are radially arranged; a second positive electrode active material including a lithium nickel-based composite oxide and being in a form of single particles; a solid electrolyte; a conductive agent; and a binder.