PIM Electrolyte Membrane for Fuel Cells With Stable Acid Retention
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Solution Overview
Problem
High temperature polymer electrolyte membrane fuel cells face issues with hydrogen ion conductivity and phosphoric acid outflow, particularly at temperatures below 140° C., which degrade cell performance.
Innovation Solution
A high temperature polymer electrolyte membrane fuel cell using a phosphoric acid-doped polymer of intrinsic microporosity (PIM) electrolyte membrane, manufactured by substituting bromine ions with hydroxide ions and impregnating with phosphoric acid, to enhance hydrogen ion conductivity and suppress acid outflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a phosphoric acid-polybenzimidazole (PA-PBI) electrolyte membrane is used at 140° C. or less, then the membrane can be operated at lower temperatures, but phosphoric acid outflow occurs and hydrogen ion conductivity is lowered
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte membrane by using PBI derivatives with specific substituents (fluorine, cyano, nitro groups) and controlling the doping level of phosphoric acid. This modifies the membrane's properties to maintain high hydrogen ion conductivity across a broader temperature range while suppressing phosphoric acid outflow at lower temperatures.
Solution Approach 2:
The patent creates a composite electrolyte membrane structure combining PBI polymer backbone with phosphoric acid doping and specific functional substituents. This composite approach integrates multiple functions: the PBI provides structural framework, phosphoric acid provides ion conduction pathways, and the functional substituents enhance thermal stability and suppress acid outflow.
2Reliability
If the operating temperature is increased to improve hydrogen ion conductivity, then conductivity increases, but phosphoric acid outflow problem worsens
Solution Approach 1:
The patent modifies the thermal and chemical parameters of the electrolyte membrane through selecting PBI derivatives with specific molecular weights and substituent patterns. These parameter changes increase the membrane's thermal retention capability, allowing it to operate at higher temperatures without phosphoric acid outflow while maintaining high hydrogen ion conductivity.
3Ease of manufacture
If a commercial PA-PBI electrolyte membrane is used, then the membrane structure is well-established, but phosphoric acid outflow occurs at temperatures of about 140° C. or less
Solution Approach 1:
The patent develops a composite electrolyte membrane using PBI derivatives with specific functional groups combined with phosphoric acid doping. This composite structure maintains the ease of manufacturing through established doping procedures while fundamentally improving phosphoric acid retention through the tailored molecular structure of the PBI derivative.
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 solution enables improved hydrogen ion conductivity across a wide temperature range and prevents phosphoric acid outflow, maintaining membrane stability and performance at high temperatures.
Implementation Method 1
hydrogen ions are conducted by phosphoric acid
Implementation Method 2
high temperature polymer electrolyte membrane fuel cell
Implementation Method 3
a dotted line may represent the electrostatic attraction between cations and anions
Implementation Method 4
impregnating the first film with an aqueous sodium hydroxide (NaOH) solution to obtain a second film including a second precursor in which bromine ions of the first precursor are substituted with hydroxide ions
Data Source
AI summary
An embodiment fuel cell including a high temperature polymer electrolyte membrane includes an electrolyte membrane including a phosphoric acid-doped polymer of intrinsic microporosity, a cathode disposed on a first surface of the electrolyte membrane, and an anode disposed on a second surface of the electrolyte membrane, the second surface opposite the first surface.