Catalyst-Free Click Polymerization of CO₂ and Lewis Monomers for Recyclable C1 Fixation and Release

Conversion of carbon dioxide (CO2) into valuable chemicals in gentle conditions is a great challenge in sustainable and energy chemistry. Here we report a CO2-participated polymerization using frustrated Lewis pair (FLP) as the monomer, which allows us to obtain well-defined CO2/FLP alternating copolymers with high molecular weights (∼50000) and quantitative conversions (∼95%), resembling a “click” polymerization of CO2 gas and FLP molecules. In comparison to other CO2-based polymerizations, this method features spontaneity, catalyst-free, and speediness, as well as can realize in ambient temperature (20 °C) and low CO2 pressure conditions (1.0 atm). Moreover, owing to the dynamic covalent bonding between CO2 and FLP unit, such a class of alternating copolymers upon heating can depolymerize into initial monomers and release CO2, which could make them as recyclable smart materials for reversible C1 fixation and release

FeCoP₂ Nanoparticles Embedded in a Hybrid Carbon Matrix as a High Performance Bifunctional Catalyst of the Advanced Zinc–Air Battery

The novel catalyst (FeCoP2-CNC) is constructed by inserting the bimetallic phosphide into a hybrid carbon substrate. The structures associated with the active sites are optimized by incorporating ultrafine cellulose fibers as a carbon source. The increased graphitic-N and metal-N species in the carbon matrix, with the enlarged specific surface area, improves the performance of catalyzing oxygen reduction reaction. The increased proportion of surface metal hydroxide active sites improves the performance of catalyzing oxygen evolution reaction. As a high performance bifunctional catalyst, the FeCoP2-CNC is applied to a rechargeable zinc–air battery and exhibits excellent performance in the battery. The solid-state zinc–air battery has achieved an excellent power density (76.9 mW cm–2) and can cycle over 45 h. The solid-state zinc–air batteries are integrated into 2 × 2 and 3 × 3 modules to power practical devices. This work provides efficient approaches to enhance the performance of bifunctional catalysts, promoting the application of zinc–air batteries

Summary of hydrogen bonding and LIE analysis for CATCH single bilayer structures.

Hydrogen bonds and salt bridges were calculated using geometric criteria: an angle cutoff of 135° and a distance cutoff of 3.0Å. Salt bridges were defined to be between the hydrogens on lysine’s ammonium group and the oxygens on glutamic acid or on aspartic acid’s α-carboxylic acid group. Salt bridge VDW and ELE interactions were calculated between the atoms on the lysine’s ammonium group and the atoms on glutamic acid and aspartic acid’s carboxylic acid group. VDW interactions between charged residues are calculated using the LIE approach and exclude backbone atoms. Values listed are averaged over three independent simulations.</p

Fig 5 -

Snapshots of (A-B) CATCH(6K+/6E-) and (C-D) CATCH(6K+/6D-) two stacked bilayers before and after 200 ns of simulation. Distances between the second and third layer of each structure are indicated.</p

Fig 1 -

(A) Schematic of CATCH peptide sequence and sidechain structure for CATCH(6K+) in blue, (6E-) in red and (6D-) in orange, (B) Front view of CATCH(6K+/6E-) and CATCH(6K+/6D-) fibril showing two stacked bilayer starting structures built in PACKMOL and rendered in Chimera.[10,11] Sidechain structures are represented using sticks and colored based on the schematic from (A). Backbones are represented using black arrows and are directed into or out of the page. (C) Side view of CATCH(6K+/6E-) and CATCH(6K+/6D-) system.</p

Fig 7 -

(A) Quantitative assessment of hydrogen bond formation over DMD simulation. (B) Analysis of free peptide depletion (orange), oligomerization (purple), and fibrillization (black).</p

Morphology of CATCH(6K+/6E-) and CATCH(6K+/6D-) co-assemblies.

(A) Cryogenic TEM micrographs of CATCH(6K+/6E-) and CATCH(6K+/6D-) in the sol state (1 mM total peptide). (B) Cryogenic SEM micrographs of CATCH(6K+/6E-) and CATCH(6K+/6D-) in the gel state (12 mM total peptide).</p

Final snapshots of CATCH(6K+/6E-) and CATCH(6K+/6E-) separated bilayer simulations after 200 ns MD simulation.

(A) Top row shows side views for three independent simulations of CATCH(6K+/6E-) separated bilayer simulations. (B) Bottom row shows side views for three independent simulations of CATCH(6K+/6E-) separated bilayer simulations. (TIF)</p

Bimetallic Sulfides Embedded in a Boron Modulated Carbon Matrix as the Bifunctional Catalyst with a Low Oxygen Evolution Reaction Overpotential for an Advanced Zinc-Air Battery

A composite bifunctional catalyst (FeNiS-NBC/C) was prepared with iron nickel sulfide nanoparticles embedded in a hybrid carbon matrix. The unique introduction of the boron element modulated the structure in achieving an ultralow oxygen evolution reaction (OER) overpotential. The incorporation of cellulose in the synthesis has improved the oxygen reduction reaction (ORR) performance. In the two-step synthesized FeNiS-NBC/C, a mixed transport network formed, with enhanced heterostructures and abundant catalytic sites. FeNiS-NBC/C exhibits the OER overpotential of 216 mV at the current density of 10 mA cm–2, as well as with the excellent ORR performance. The low OER overpotential reduces the oxidation corrosion in the rechargeable zinc-air batteries. The zinc-air battery with a liquid electrolyte assembled using FeNiS-NBC/C exhibited the power density of 133.0 mW cm–2 and specific capacity of 797.8 mAh g–1. The solid-state zinc-air battery assembled using FeNiS-NBC/C exhibited the power density of 61.4 mW cm–2 and can be stably charge–discharge cycled for 46 h. This work pointed out a novel avenue to construct bifunctional catalysts in the future for advanced zinc-air batteries

Gel Polymer-Based Composite Solid-State Electrolyte for Long-Cycle-Life Rechargeable Zinc–Air Batteries

Developing high-performance, safe, and flexible solid-state electrolytes (SSEs) for rechargeable solid-state zinc–air batteries (ZABs) is becoming increasingly crucial but remains fraught with tremendous challenges. Herein, a novel multinetwork cross-linked composite gel electrolyte (PVAA-Cellulose) was constructed by introducing poly­(acrylic acid) (PAA) and ultrafine cellulose to the poly­(vinyl alcohol) (PVA) gel electrolyte. By virtue of the extensive porous network and hydrogen bonding, the PVAA-Cellulose SSEs achieve optimal water retention, thermal stability, and high ionic conductivity of 123 mS cm–1 compared with PVAA (mixture of PVA and PAA). The investigation of the effects of different SSEs on zinc anodes after ZAB cycling reveals that PVAA-Cellulose SSE can effectively inhibit dendrite growth and oxidation byproduct generation on zinc anodes, which contributes to the long-term cycling stability of ZABs. As a result, solid-state ZABs assembled with PVAA-Cellulose SSEs possess a high power density of 74 mW cm–2, a specific capacity of 724 mAh gZn–1, and a long cycle stability of 54 h as well as the outstanding flexibility exhibited by the flexible ZAB devices