Graphite Complex Particles for Solid-State Battery Anode Contact Loss
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Solution Overview
Problem
The use of solid electrolytes in all-solid type batteries results in reduced electrochemical reaction sites and capacity due to insufficient contact between the active material and the electrolyte, leading to capacity and output reduction.
Innovation Solution
The development of complex particles comprising graphite particles filled with a mixture of a solid electrolyte and a conductive material, formed through a mechanical granulation process, to enhance contact area and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spherical graphite particles are used as negative electrode active material with solid electrolyte, then battery safety and reliability are improved, but contact area between electrolyte and active material is reduced, resulting in capacity and output reduction
Solution Approach 1:
The invention utilizes porous carbon particles with controlled porosity (30-70%) to maintain sufficient contact area between solid electrolyte and active material. The porous structure allows solid electrolyte to penetrate and contact internal surfaces, preventing capacity loss while maintaining battery safety benefits of solid electrolyte.
Solution Approach 2:
The invention employs composite carbon particles combining conductive material (5-70 wt%), porous material (5-70 wt%), and binder (5-30 wt%). This composite structure ensures both electrical conductivity and sufficient electrolyte contact, resolving the contradiction between safety and capacity.
2Reliability
If spherical graphite particles are used as negative electrode active material with solid electrolyte, then battery safety and reliability are improved, but contact area between electrolyte and active material is reduced, resulting in output reduction
Solution Approach 1:
The porous structure with 30-70% porosity provides extensive internal surface area for solid electrolyte contact, enabling sufficient ionic conductivity pathways. This maintains high output performance while preserving the safety advantages of solid electrolyte.
Solution Approach 2:
The invention replicates the beneficial liquid electrolyte penetration effect using solid electrolyte by creating a porous carbon structure that allows solid electrolyte to access internal surfaces, thereby maintaining high power output while achieving solid electrolyte safety benefits.
3Ease of manufacture
If pores in graphite particles remain empty with solid electrolyte, then manufacturing simplicity is maintained, but electrochemical reaction sites are reduced
Solution Approach 1:
The invention deliberately designs porous carbon particles with controlled porosity (30-70%) to ensure solid electrolyte penetration. This simple structural design maintains ease of manufacture while dramatically increasing electrochemical reaction sites through internal surface area.
Solution Approach 2:
The invention applies local quality by creating porous regions within carbon particles specifically designed to accommodate solid electrolyte. This localized porous structure increases reaction sites without complicating the overall manufacturing process.
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 complex particles maintain high density and electrochemical performance, preventing capacity and output reduction, and enabling high ion and electron conduction paths within the active material.
Implementation Method 1
the electrolyte can penetrate into the pores in the graphite particles... the contact area between the electrolyte and the active material particles... resulting in reduced capacity and output
Implementation Method 2
a mixture including a solid electrolyte and a conductive material fills gaps between the graphite materials of the graphite particles
Data Source
AI summary
Complex particles for a negative electrode active material according to the present disclosure have no problem with reduced capacity and output by virtue of sufficient electrochemical reaction sites between a solid electrolyte and an electrode active material. The complex particles according to the present disclosure include carbon particles of a carbon material such as flaky graphite, which are spherical in shape by shape modification, and a solid electrolyte and a conductive material filled between the particles, and thus have the increased contact area between the active material and the solid electrolyte increases, and ion conduction and electron conduction paths extended and maintained to the inside of the active material particles.