Cathode Active Material for Potassium Secondary Batteries, Method for Manufacturing the Same, and Potassium Secondary Battery Comprising the Same

High-Voltage, Long-Life Potassium Battery Cathode Material Based on Strontium-Substituted Vanadium Oxide Layered Structures

This technology features a cathode active material based on a vanadium oxide (V2O5) layered structure, where a portion of the potassium (K) sites are substituted with electrochemically inert strontium (Sr). This ensures structural stability during charge and discharge cycles while improving ion transport rates and lifespan.

Due to the large ionic radius of potassium, the insertion and extraction processes place significant stress on the crystal structure. Furthermore, the wide interlayer spacing leads to severe side reactions with the electrolyte, and the collapse of the crystal structure during long-term cycling has historically limited both lifespan and capacity.

This technology forms strong Sr-O bonds by substituting a portion of the potassium in the K-V-O layered structure with strontium at a K:Sr atomic ratio of 2–15:1. Using a hydrothermal synthesis method, we produce nanoparticles with an average size of 200–800 nm, enhancing both electrochemical and mechanical properties. Applicable to potassium-ion battery and low-cost energy storage system production lines, this material reduces reliance on lithium resources and maintains a stable layered framework even under high-voltage conditions exceeding 4.2V.

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Key Features:

• Strontium included in a potassium-based layered structure at an atomic ratio of 2–15:1 relative to potassium
• A cathode active material comprising both a potassium-only layer and a substituted layer where a portion of the potassium is replaced by strontium
• A cathode active material in the form of nanoparticles with an average diameter of 200 nm to 800 nm, produced via hydrothermal synthesis
• A process involving dissolving potassium, vanadium, and strontium compounds in a first solvent, then maintaining the mixture at high temperature and pressure in an autoclave to produce a solid material

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This invention was developed with support from the Ministry of Science and ICT for the development of high-voltage layered cathode materials for high-energy-density potassium-ion batteries.

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