Permselective anion exchange membranes (AEMs) are of great interest in electrochemical devices, allowing the selective transport of species of interest through the membrane while preventing the crossover of undesired substrates. However, porous and nonporous membranes have traditionally been developed and applied separately for these applications. In this study, we utilized the merits of polymerization-induced microphase separation to observe the transition from porous to nonporous membranes by controlling the etchable block length and the hydrophilic domain size, respectively. At a certain point, a transition from porous to nonporous permeation behavior was observed, where permeation no longer depended on the open pore size. For the fabrication of AEMs with well-defined and 3D continuous nanochannels, we integrated an etchable sacrificial block with a pre-functional block containing precursors for quaternary ammonium groups to create a pore decorated with positively charged dangling chains. Etching and amination yielded the target AEM with a controlled pore size and ammonium ion density. Increasing the length of the dangling chains resulted in nonporous AEMs, which allowed exclusive permeation of a negatively charged dye over a positive one. This provides strong evidence that the solution-diffusion model applies to nonporous membranes. Tunable permselectivity over a wide range, combined with stability in organic solvents and alkaline conditions, suggests that this methodology holds significant potential for the development of membranes for advanced electrochemical systems.

Despite extensive studies on nanoporous membranes for regulating lithium-ion (Li⁺) flux in lithium (Li)-metal batteries, the pore size design has largely focused on very small (< 5 nm) or extremely large (> 20 nm) dimensions, overlooking the intermediate pore size range. This gap, particularly between 5 and 15 nm, has limited exploration of critical Li⁺ transport phenomena and their impact on improving cell performance. Here, we developed robust and free-standing polymeric films with three-dimensional (3D) continuous nanoporous channels, precisely tuned to pore diameters ranging from 5 to 14 nm and immobilized sulfonate groups. Our systematic investigations revealed how pore size and immobilized anionic groups correlated with Li⁺ conductivity and battery performance. Notably, sulfonate-functionalized channels promoted Li⁺ conductivity significantly within this optimal pore range compared to non-functionalized counterparts. In an ether-based electrolyte with 1 M lithium bis(fluorosulfonyl)imide (LiFSI), the Li⁺ conductivity peaked at a pore diameter of 10 nm. Furthermore, the mobility of Li⁺ was approximately 4.4 times faster than FSI⁻, resulting in reducing interfacial resistance and promoting uniform Li deposition. The sulfonated nanoporous membrane in Li|LiFePO₄ full cells with an N/P ratio of 2.3 delivered excellent cycling stability over 1000 cycles while retaining approximately 80 % of the initial capacity.

We report a new bottlebrush copolymer (BBCP) ligand design as robust patches for gold nanoparticles (Au NPs) to construct a rigid template guiding heterometal deposition on the surface. Given the spatial congestion of the side chains, the BBCP rapidly forms dense and stationary patches on Au NPs and effectively blocks additional metal deposition. Reducing solvent quality varies the phase segregation of the BBCP and subsequently restricts metal deposition to specific locations, fabricating diverse bimetallic heterostructures. The resulting morphology exhibits a unique orientation-dependent scattering property that thermodynamic configuration cannot achieve.

We developed a block polymer-based synthetic route to sulfonated porous composites (SPCs) with precisely controlled nanopore size. By reducing the pore size to <4 nm and introducing a high density of surface sulfonic acid, the permeation of vanadium ions was effectively suppressed. We employed a polymerization-induced microphase separation (PIMS) process, in which a polyethylene fiber mat impregnated with a liquid polymerization mixture was spontaneously transformed into a fiber-reinforced and cross-linked block polymer membrane. Selective etching and sulfonation then produced the target composite membrane. In a vanadium redox flow battery (VRFB) cell, an SPC with 3.6 nm-sized mesopores, 109 m2 g–1 of specific surface area, and 0.3 mL g–1 of mesoporosity outperformed a Nafion 212 membrane of similar thickness, providing higher proton conductivity and much lower vanadium permeability. Thanks to the composite reinforcement, the membrane demonstrated remarkably enhanced mechanical stability. The SPC membrane could be successfully operated up to 300 cycles. Compared with Nafion 212, the SPC exhibited higher energy efficiencies (EEs) and higher discharge capacity retention. These results suggest the promise of block polymer-based permselective membranes in advanced battery applications.

Recently, because of rapid advances in electrical vehicles, unmanned air vehicles, and humanoid mobile robots, structural energy storage devices with a concurrent capability to store electrochemical energy and to support mechanical loads have been in the spotlight. However, a big hurdle to realizing an integrated electro-chemo-mechanical system is to develop highly compatible active electrodes and structural electrolytes with superior mechanical strength and electrochemical functionality while retaining light weight. We report a load-bearing structural supercapacitor by utilizing a bicontinuous PEO-b-P(S-co-DVB) structural electrolyte and carbon-coated Ni-Co nanowires grown on carbon fiber woven fabric. A liquid polymerization mixture between the electrodes is transformed into a solid-state block copolymer electrolyte, preserving conformal contact with the nanostructured electrode surface. The polymerization-induced microphase separation produces a bicontinuous morphology of cross-linked hard domain and liquid-like conductive domain in the electrode, providing high modulus and high conductivity. The resulting structural supercapacitor is able to operate under tensile and even bending load, suggesting its wide potential applications.