A grand challenge in material science is to understand the correlation between intrinsic properties and defect dynamics. Radiation tolerant materials are in great demand for safe operation and advancement of nuclear and aerospace systems. Unlike traditional approaches that rely on microstructural and nanoscale features to mitigate radiation damage, this study demonstrates enhancement of radiation tolerance with the suppression of void formation by two orders magnitude at elevated temperatures in equiatomic single-phase concentrated solid solution alloys, and more importantly, reveals its controlling mechanism through a detailed analysis of the depth distribution of defect clusters and an atomistic computer simulation. The enhanced swelling resistance is attributed to the tailored interstitial defect cluster motion in the alloys from a long-range one-dimensional mode to a short-range three-dimensional mode, which leads to enhanced point defect recombination. The results suggest design criteria for next generation radiation tolerant structural alloys.

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Aryl‐ether‐free anion‐exchange ionomers (AEIs) and membranes (AEMs) have become an important benchmark to address the insufficient durability and power‐density issues associated with AEM fuel cells (AEMFCs). Here, we present aliphatic chain‐containing poly(diphenyl‐terphenyl piperidinium) (PDTP) copolymers to reduce the phenyl content and adsorption of AEIs and to increase the mechanical properties of AEMs. Specifically, PDTP AEMs possess excellent mechanical properties (storage modulus>1800 MPa, tensile strength>70 MPa), H2 fuel‐barrier properties (<10 Barrer), good ion conductivity, and ex‐situ stability. Meanwhile, PDTP AEIs with low phenyl content and high‐water permeability display excellent peak power densities (PPDs). The present AEMFCs reach outstanding PPDs of 2.58 W cm−2 (>7.6 A cm−2 current density) and 1.38 W cm−2 at 80 °C in H2/O2 and H2/air, respectively, along with a specific power (PPD/catalyst loading) over 8 W mg−1, which is the highest record for Pt‐based AEMFCs so far.

Poly(fluorenyl-co-aryl piperidinium)-based AEMWEs reach outstanding current density values of 7.68 A cm−2 at 2.0 V with a cell durability of 1000 h.

Low-cost anion exchange membrane fuel cells have been investigated as a promising alternative to proton exchange membrane fuel cells for the last decade. The major barriers to the viability of anion exchange membrane fuel cells are their unsatisfactory key components—anion exchange ionomers and membranes. Here, we present a series of durable poly(fluorenyl aryl piperidinium) ionomers and membranes where the membranes possess high OH− conductivity of 208 mS cm−1 at 80 °C, low H2 permeability, excellent mechanical properties (84.5 MPa TS), and 2000 h ex-situ durability in 1 M NaOH at 80 °C, while the ionomers have high water vapor permeability and low phenyl adsorption. Based on our rational design of poly(fluorenyl aryl piperidinium) membranes and ionomers, we demonstrate alkaline fuel cell performances of 2.34 W cm−2 in H2-O2 and 1.25 W cm−2 in H2-air (CO2-free) at 80 °C. The present cells can be operated stably under a 0.2 A cm−2 current density for ~200 h.

Anion-exchange membrane fuel cells (AEMFCs) are a promising, next-generation fuel cell technology. AEMFCs require highly conductive and robust anionexchange membranes (AEMs), which are challenging to develop due to the tradeoff between conductivity and water uptake. Here we report a method to prepare high-molecularweight branched poly(aryl piperidinium) AEMs. We show that branching reduces water uptake, leading to improved dimensional stability. The optimized membrane, b-PTP-2.5, exhibits simultaneously high OH À conductivity (> 145 mS cm À 1 at 80 °C), high mechanical strength and dimensional stability, good processability, and excellent alkaline stability (> 1500 h) in 1 M KOH at 80 °C. AEMFCs based on b-PTP-2.5 reached peak power densities of 2.3 W cm À 2 in H 2 À O 2 and 1.3 W cm À 2 in H 2 -air at 80 °C. The AEMFCs can run stably under a constant current of 0.2 A cm À 2 over 500 h, during which the b-PTP-2.5 membrane remains stable.

A novel cobaltocenium-containing polybenzimidazole polymer was used for alkaline anion exchange membranes.

In response to prepare high-stable and ion-conducting polyelectrolyte for hydroxide exchange membrane (HEM) applications, we present an ultrastable polyelectrolyte based on six-membered heterocyclic 6-azonia-spiro[5.5]undecane (ASU) and polyphenyl ether (PPO). A series of ASU-functionalized PPO polyelectrolytes (ASU-PPO), which can be easily dissolved in low-boiling pointing solvent, have been successfully synthesized by a remote-grafting method. The ASU precursor is stable in 1 M NaOH/DO at 80 °C for 2500 h as well as in 5 M NaOH/DO at 80 °C for 2000 h, and the predicted half-life of the ASU precursor would exceed 10 000 h, even higher in the future. Besides, these remote-grafting ASU-PPO polyelectrolytes are stable in 1 M NaOH at 80 °C for 1500 h. Robust and pellucid segmented ASU and triple-ammonium-functionalized PPO-based HEMs attach OH conductivity of 96 mS/cm at 80 °C and realize maximal power density of 178 mW/cm under current density of 401 mA/cm.