Low-Voltage Electrolyzer Using pH Buffers to Limit Ion Migration
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Solution Overview
Problem
Existing electrolyzers, such as chlor-alkali electrolyzers, require high energy consumption due to the migration of protons and hydroxides across ion-selective barriers, leading to increased voltage requirements and inefficiencies.
Innovation Solution
Incorporating a pH buffer in the catholyte and/or anolyte to retain anions and cations within their respective compartments, and utilizing the gas generated at one electrode to be consumed at the other electrode, reducing the need for additional ion-selective barriers and minimizing proton and hydroxide migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional chlor-alkali electrolyzers are used, then acid and base can be produced, but energy consumption is high due to proton and hydroxide migration across ion-selective barriers
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing pH buffers (weak acids and their conjugate bases) to control the proton concentration and migration behavior, thereby reducing energy consumption while maintaining production efficiency
Solution Approach 2:
The patent uses pH buffers as intermediary substances that mediate between the ion-selective barriers and the electrochemical reactions, controlling proton and hydroxide migration to reduce energy loss while maintaining acid and base production
2Power
If ion-selective barriers are used to separate compartments, then acid and base production is enabled, but voltage requirements increase due to proton and hydroxide migration
Solution Approach 1:
The patent modifies the electrolyte composition by adding pH buffers to change the proton concentration and migration characteristics, reducing the voltage required across ion-selective barriers while maintaining Faradaic efficiency above 90%
Solution Approach 2:
The patent converts the harmful effect of proton migration (which increases voltage requirements) into a beneficial process by using pH buffers to control and utilize proton movement for acid production while minimizing energy loss
3Ease of operation
If gas generated at one electrode is allowed to escape, then operational simplicity is maintained, but energy efficiency decreases due to loss of reactive species
Solution Approach 1:
The patent merges the functions of gas evolution and gas consumption into a single integrated system where hydrogen gas generated at the cathode is immediately consumed at the anode, eliminating the need for separate gas handling systems while improving energy efficiency
Solution Approach 2:
The patent implements a self-service system where the hydrogen gas produced by the cathode automatically serves the anode by being consumed in the electrochemical reaction, eliminating the need for external gas management while maximizing energy utilization
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 design reduces the overall energy consumption by up to 50% compared to traditional electrolyzers, achieving an open-circuit potential of less than 1 volt and improving Faradaic efficiency to above 90%, while allowing for the generation of acids and bases with moderate concentrations.
Implementation Method 1
a cathode compartment configured to generate a gas
Implementation Method 2
the anode-containing compartment is configured to receive the hydrogen gas and oxidize the hydrogen gas generating protons
Implementation Method 3
a first ion-selective barrier separating the cathode compartment from the anode compartment and a second ion-selective barrier separating the anode-containing compartment from the anolyte compartment
Implementation Method 4
the anolyte compartment is configured to maintain a pH between 1 and 6
Data Source
AI summary
Disclosed herein are low voltage electrolyzers and methods and systems of using those low voltage electrolyzers. Specifically, the electrolyzers can include a pH buffer in the catholyte and/or anolyte of the electrolyzer and generating a gas at the cathode or anode that is consumed at the other of the cathode or anode to reduce the open-circuit potential.