High Free Volume Polyelectrolytes for Anion Exchange Membrane Water Electrolyzers with a Current Density of 13.39 A cm−2 and a Durability of 1000 h

Abstract The rational design of the current anion exchange polyelectrolytes (AEPs) is challenging to meet the requirements of both high performance and durability in anion exchange membrane water electrolyzers (AEMWEs). Herein, highly‐rigid‐twisted spirobisindane monomer is incorporated in poly(aryl‐co‐aryl piperidinium) backbone to construct continuous ionic channels and to maintain dimensional stability as promising materials for AEPs. The morphologies, physical, and electrochemical properties of the AEPs are investigated based on experimental data and molecular dynamics simulations. The present AEPs possess high free volumes, excellent dimensional stability, hydroxide conductivity (208.1 mS cm−1 at 80 °C), and mechanical properties. The AEMWE of the present AEPs achieves a new current density record of 13.39 and 10.7 A cm−2 at 80 °C by applying IrO2 and nonprecious anode catalyst, respectively, along with outstanding in situ durability under 1 A cm−2 for 1000 h with a low voltage decay rate of 53 µV h−1. Moreover, the AEPs can be applied in fuel cells and reach a power density of 2.02 W cm−2 at 80 °C under fully humidified conditions, and 1.65 W cm−2 at 100 °C, 30% relative humidity. This study provides insights into the design of high‐performance AEPs for energy conversion devices.


Figure S2
. 1 H NMR spectrum of TTSBD using DMSO-d6 as the solvent.

Figure S3
. 13 C NMR spectrum of TTSBD using DMSO-d6 as the solvent.
OH -conductivity (mS cm

Figure S15 .
Figure S15.The thermal stability of PSAP-m from 50 to 750°C with a heating rate of 10°C/min under a N2 atmosphere.(a) PSTP-m, (b) PSBP-m, (c) PSDP-m membranes in I − form.

Figure S19 .
Figure S19.The radial distribution function (RDF) analysis of (a) N-OH -pair, (b) N pair in the wet state, (c) N pair in the dry state of PSTP-m and PSBP-m AEMs.As a result of RDF analysis of the N-OH -pair, the structure of PSTP-m is more closely distributed with N atoms and OH -ions compared to PSBP-m.As a result of RDF analysis of the N pair, the peak decreased as the water uptake increased in the wet state.In the dry form for the N pair, PSBP-m showed a more substantial peak than PSTPm.

Table S1 .
The solubility of PSAP-m polymers in common organic solvents The comparison of water electrolysis and durability with state-of-the-art AEMWEs ↓: insoluble; ↑: soluble; ━: partially solubleTable S2.

Table S3 .
The comparison of fuel cell performance with state-of-the-art AEMFCs

Table S4 .
Polymer building parameters