Cubic Solid Electrolyte for All-Solid Battery Ion Conductivity
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Solution Overview
Problem
Solid electrolytes used in all-solid secondary batteries have insufficient ion conductivity, limiting their performance compared to batteries with liquid electrolytes.
Innovation Solution
A solid electrolyte with a lithium-containing phosphoric acid compound in a cubic crystal structure is used, which enhances ion conductivity by providing three-dimensionally symmetric conducting paths and includes bound water to stabilize the crystal structure and improve conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If triclinic or rhombohedral crystal solid electrolytes are used, then reduction resistance is improved, but ion conductivity deteriorates
Solution Approach 1:
The invention changes the crystal structure parameter from triclinic/rhombohedral to cubic system, and optimizes compositional parameters (Li content x=1.05-2.0, M1 y=0.01-0.5, M2 z=0.01-0.5) to achieve both high ion conductivity (≥10⁻⁵ S/cm) and adequate reduction resistance. The cubic crystal structure provides three-dimensional symmetric ion conduction paths while the optimized composition maintains structural stability.
Solution Approach 2:
The invention uses composite materials by incorporating multiple elements (Li, M1, M2, M3, P, O) in specific ratios to form a cubic crystal structure. The composite composition LixM1yM2zM3wP3-wO12 combines different metal elements to achieve both high ion conductivity and reduction resistance simultaneously, rather than using a single element compound.
2Reliability
If all-solid secondary batteries are used, then safety is improved by eliminating liquid leakage, but output deteriorates due to lower ion conductivity
Solution Approach 1:
The invention changes the physical state parameter of the electrolyte from liquid to solid, eliminating safety issues of liquid leakage. Simultaneously, it optimizes the crystal structure parameter to cubic system and compositional parameters to achieve ion conductivity ≥10⁻⁵ S/cm, enabling the solid-state battery to reach output levels comparable to or exceeding liquid electrolyte batteries while maintaining safety advantages.
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 solid electrolyte with a cubic crystal structure significantly increases ion conductivity, reducing voltage loss and enhancing the capacity of all-solid secondary batteries.
Implementation Method 1
a solid electrolyte including a lithium-containing phosphoric acid compound which is a cubic crystal... it is possible to enhance ion conductivity
Implementation Method 2
includes bound water to stabilize the crystal structure and improve conductivity
Data Source
AI summary
A solid electrolyte according to an embodiment includes a lithium-containing phosphoric acid compound with a cubic crystal structure.