All-Solid-State Cathode Grain Orientation for Lower Interfacial Resistance
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Solution Overview
Problem
All-solid-state lithium metal batteries face challenges with high interfacial resistance at the solid electrolyte/electrode interface, leading to deteriorated battery performance, and existing solutions often require additional materials or processes that compromise energy density and increase processing costs.
Innovation Solution
A cathode for all-solid-state batteries featuring a grain with a grain boundary parallel to the electron movement direction and predominantly having a plane with low surface energy, specifically a compound represented by LiaNibMcNdLeOx with a spinel structure, which suppresses the dissolution and diffusion of transition metals, thereby improving interfacial characteristics without introducing additional materials or processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid electrolyte is used, then interfacial resistance is lower, but flammability and safety issues arise
Solution Approach 1:
The invention changes the physical state of the electrolyte from liquid to solid, fundamentally altering the interface characteristics between electrolyte and electrode. This parameter change enables non-flammable operation while the specific crystal plane orientation and grain boundary configuration reduce solid-solid interfacial resistance
Solution Approach 2:
The invention applies local quality by specifically orienting certain crystal planes (low surface energy planes) parallel to the electrode interface and controlling grain boundary orientations. This creates localized regions with optimal electrical contact and minimal resistance at the critical electrode-electrolyte interface, while maintaining the overall solid electrolyte structure for safety
2Object-affected harmful factors
If additional materials are introduced to improve interface characteristics, then interfacial resistance decreases, but energy density decreases and processing costs increase
Solution Approach 1:
The invention enables the solid electrolyte to self-optimize its interface characteristics through controlled crystal growth. By orienting low surface energy crystal planes and controlling grain boundary formations during the sintering process, the electrolyte automatically creates optimal contact with the electrode without requiring additional interfacial materials or complex processing steps
Solution Approach 2:
The invention creates a composite structure at the micro level by combining the solid electrolyte with specifically oriented crystal planes and controlled grain boundaries. This internal composite architecture provides both low interfacial resistance and high energy density without introducing external materials that would reduce the quantity of active substances
3Object-affected harmful factors
If additional processes are introduced to improve interface characteristics, then interfacial resistance decreases, but processing costs increase
Solution Approach 1:
The invention performs preliminary action by controlling the crystal orientation and grain boundary formation during the initial sintering process. By establishing the optimal crystal plane orientation parallel to the electrode interface before electrode assembly, the need for subsequent complex interface modification processes is eliminated, reducing manufacturing complexity and cost
Data Source
AI summary
Disclosed are a cathode for an all-solid-state battery including a cathode thin film for an all-solid-state battery or a cathode composite membrane for an all-solid-state battery, and an all-solid-state battery including the same. The cathode for an all-solid-state battery contains a grain that has a plane having a low surface energy and has a grain boundary arranged parallel to the electron movement direction, thus effectively lowering the interfacial resistance of the thin film while suppressing the dissolution and diffusion of the transition metal, thereby improving the cycle stability of the all-solid-state battery including the same.