Electrode Material Hopping Conduction Resistivity
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Solution Overview
Problem
Conventional metal oxide electrode materials exhibit increased resistivity upon stabilization of their crystal structure, leading to reduced flowability of electricity and limited improvement in storage characteristics, as they primarily rely on band conduction rather than hopping conduction.
Innovation Solution
An electrode material with an average particle size of 50 μm or less and an activation energy of 0.05 eV or less is developed, exhibiting hopping conduction characteristics at room temperature, which enhances electron delivery efficiency and charge/discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed in an oxidizing atmosphere to stabilize the crystal structure, then storage characteristics are improved, but resistivity increases and flowability of electricity is reduced
Solution Approach 1:
The patent changes the atmosphere parameter from oxidizing to reducing during heat treatment. This parameter change transforms the conduction mechanism from band conduction to hopping conduction, achieving low resistivity while maintaining crystal structure stability. The reducing atmosphere creates oxygen defects that enable hopping conduction with activation energy of 0.05 eV or less.
Solution Approach 2:
The patent creates a composite state within the metal oxide powder by combining stabilized crystal structure with oxygen defects. This composite structure allows simultaneous achievement of storage characteristics (from stabilized structure) and high conductivity (from hopping conduction via oxygen defects).
2Stability of the object's composition
If band conduction is used in stabilized metal oxide powder, then crystal structure stability is achieved, but charge/discharge efficiency and speed are limited
Solution Approach 1:
The patent changes the conduction mechanism parameter by controlling activation energy to be 0.05 eV or less through heat treatment in reducing atmosphere. This transforms the conduction type from band conduction to hopping conduction, enabling fast charge/discharge while maintaining crystal structure stability.
Solution Approach 2:
The patent induces a transition in the conduction phase from band conduction to hopping conduction. This phase transition is achieved by creating oxygen defects in the crystal structure through heat treatment in reducing atmosphere, fundamentally changing how electricity is conducted while preserving structural stability.
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 electrode material achieves improved charge/discharge efficiency, increased charge/discharge speed, and extended battery life by utilizing hopping conduction, maintaining optimal performance across a wide temperature range.
Implementation Method 1
the conduction mechanisms indicating the flowability of electricity of an electrode material are roughly classified into two types, which are band conduction and hopping conduction. Such an electrode material has hopping conduction characteristics at room temperature (25° C.)
Data Source
AI summary
The present invention provides an electrode material comprising at least one of metal compound powder and carbon powder, the powder having an average particle size of 50 μm or less and an activation energy Eα of 0.05 eV or less. Further, the powder preferably has hopping conduction characteristics at room temperature of 25° C. Furthermore, the powder preferably has an amount of oxygen defects of 1×1018 cm−3 or more. Still further, the powder preferably has a carrier density of 1×1018 cm−3 or more. Due to above structure, there can be provided an electrode material having a high storage capacity and a high charge/discharge efficiency.