Na-Li-Ru Oxide Cathode Tunnel Structure for Lithium Battery Stability
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Solution Overview
Problem
Conventional lithium secondary batteries face issues with structural deformation and safety due to volume changes during lithium ion intercalation and deintercalation, particularly in electric vehicles and large-capacity power storage devices, where cobalt-based materials are expensive and prone to manganese elution, and alternative materials like hollandite structures are unstable.
Innovation Solution
A Na—Li—Ru-based oxide compound is developed with a tunnel structure formed by MO6 octahedrons, where Li ions are substituted into hollows using an ion substitution method, maintaining a stable crystal structure during charge and discharge, preventing structural deformation and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium cobalt composite oxide with layered structure is used for cathode, then high energy density and high discharge voltage are achieved, but structural deformation occurs due to volume changes during Li cation intercalation and deintercalation
Solution Approach 1:
The patent changes the crystal structure parameter from layered structure to tunnel structure, and changes the host cation from Li to Na, creating a structure that maintains stability during Li intercalation/deintercalation while preserving high energy density characteristics
Solution Approach 2:
The patent uses composite material strategy by combining Na-Ru-O tunnel structure with Li cation insertion, creating a hybrid system that leverages the structural stability of Na-Ru-O tunnel structure and the high energy density of Li-based cathode materials
2Stability of the object's composition
If lithium cobalt composite oxide with spinel structure is used, then volume stability is improved, but manganese elution occurs at high temperature and high current
Solution Approach 1:
The patent changes the metal composition parameter by substituting Mn with Ru in the tunnel structure, eliminating the manganese elution problem while maintaining volume stability during Li intercalation/deintercalation cycles
3Stability of the object's composition
If hollandite structure with 1-dimensional tunnel is used, then Li cation intercalation and deintercalation stability is improved, but structural instability occurs when metals with large ion size are absent
Solution Approach 1:
The patent changes the host cation parameter from Li to Na in the tunnel structure, creating a more stable framework that maintains structural integrity and long lifespan during repeated Li intercalation/deintercalation cycles
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 compound ensures high energy density, long lifespan, and safety for lithium secondary batteries, particularly in electric vehicles and large-capacity power storage devices, by maintaining structural stability during repeated charge and discharge cycles and preventing overcharge-induced deformation.
Implementation Method 1
Li cations substituted instead of Na cations using an ion substitution method are present in the hollows
Data Source
AI summary
Disclosed are a novel compound, a method for preparing the same, and a lithium secondary battery comprising the same. More specifically, disclosed are a compound in which five MO6 octahedrons are bonded to one another around one MO6 octahedron such that the MO6 octahedrons share a vertex, to form hollows and Li cations substituted instead of Na cations using an ion substitution method are present in the hollows, and a crystal structure thereof is not varied even upon intercalation and deintercalation of Li cations, a method for preparing the same, and a lithium secondary battery comprising the same as a cathode active material.