Redox Flow Battery Multiple Electroactive Elements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Redox flow batteries face challenges with intrinsically low energy density compared to other reversible energy storage systems, primarily due to voltage limitations and solubility issues of active redox ions in aqueous systems.
Innovation Solution
Employing multiple redox pairs in both the positive and negative half-cells, utilizing redox couples such as V4+/V5+ and Fe2+/Fe3+ in the positive electrolyte and V2+/V3+ in the negative electrolyte, with a focus on improving solubility and stability through the use of chloride and sulfate supporting solutions, allowing for higher concentrations and improved thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the active species concentration is increased to improve energy density, then energy density is improved, but the concentration is limited by solubility and stability of the active redox ions
Solution Approach 1:
The patent combines multiple redox couples (V4+/V5+ and Fe2+/Fe3+ in the positive electrolyte, V2+/V3+ in the negative electrolyte) into a single battery system. This merging of multiple electroactive elements allows the system to achieve higher energy density by utilizing multiple independent redox reactions simultaneously, effectively multiplying the energy storage capacity beyond what a single redox couple could provide while maintaining solubility limits of individual species.
Solution Approach 2:
The patent employs multiple redox couples that can operate simultaneously in the same electrolyte system, making the battery capable of multiple independent electrochemical reactions. This multi-functionality allows the system to store and release energy through different redox pathways, effectively increasing the total energy density without requiring separate battery cells for each redox couple.
2Quantity of substance
If traditional sulfate systems are used, then system simplicity is maintained, but energy density is limited
Solution Approach 1:
The patent merges multiple redox couples into a single integrated battery system using a common electrolyte composition containing both sulfate and chloride ions. This approach achieves high energy density (up to 30% improvement over traditional sulfate systems) without requiring separate battery cells or complex multi-component systems, thereby maintaining relative system simplicity while substantially improving energy density.
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
This approach enhances energy density by up to 30% compared to traditional sulfate systems, reduces the need for active thermal management, and maintains high columbic and energy efficiency, while expanding the operational temperature range without increasing system complexity or cost.
Implementation Method 1
Redox flow batteries store electrical energy in reduced and oxidized species dissolved in two separate electrolyte solutions. The negative electrolyte and the positive electrolyte circulate through two cell electrodes separated by an ion conducting membrane or separator. Redox flow batteries are advantageous for energy storage because they are capable of tolerating fluctuating power supplies, repetitive charge/discharge cycles at maximum rates
Implementation Method 2
The negative electrolyte and the positive electrolyte circulate through two cell electrodes separated by an ion conducting membrane or separator
Data Source
AI summary
Introducing multiple redox reactions with a suitable voltage range can improve the energy density of redox flow battery (RFB) systems. One example includes RFB systems utilizing multiple redox pairs in the positive half cell, the negative half cell, or in both. Such RFB systems can have a negative electrolyte, a positive electrolyte, and a membrane between the negative electrolyte and the positive electrolyte, in which at least two electrochemically active elements exist in the negative electrolyte, the positive electrolyte, or both.