Changchun Ye's research while affiliated with Tongji University and other places

Developing a facile strategy to activate the inert crystal face of an electrocatalyst is critical to full‐facet utilization, yet still challenging. Herein, the electrocatalytic activity of the inert crystal face is activated by quenching Co3O4 cubes and hexagonal plates with different crystal faces in Fe(NO3)3 solution, and the regulation mechanism of facet‐dependent quench‐engineering is further revealed. Compared to the Co3O4 cube with exposed {100} facet, the Co3O4 hexagonal plate with exposed {111} facet is more responsive to quenching, accompanied by a rougher surface, richer defect, and more Fe doping. Theoretical calculations indicate that the {111} facet has a more open structure with lower defect formation energy and Fe doping energy, ensuring its electronic and coordination structure is easier to optimize. Therefore, quench‐engineering largely increases the catalytic activity of {111) facet for oxygen evolution reaction by 13.2% (the overpotential at 10 mA cm⁻² decreases from 380 to 330 mV), while {100} facet only increases by 7.6% (from 393 to 363 mV). The quenched Co3O4 hexagonal plate exhibits excellent electrocatalytic activity and stability in both zinc–air battery and water‐splitting. The work reveals the influence mechanism of crystal face on quench‐engineering and inspires the activation of the inert crystal face.

Heterostructured metal oxides exhibit outstanding catalytic performance in various chemical/electrochemical reactions, yet still face the bottleneck of synthesis difficulty and insufficient control over the catalyst composition. Herein, a facile synthesis route for heterostructured metal oxides via quenching-induced structural transformation was developed, and the size effect and the promotion mechanism between multiple quenching were also presented. Repeated quenching of hot NiMoO4 powders with a broad range of initial particle size in cold Fe(NO3)3 solution yielded different products depending on the initial NiMoO4 particle size and quenching frequency. Significant disorder and roughened surface were created on the large-grained NiMoO4 nanoparticles (> 27 nm), whilst for smaller NiMoO4 nanoparticles (< 27 nm), multiple quenching triggered the structural transformation from NiMoO4 to NiFe2O4 to create novel NiMoO4/NiFe2O4 heterostructure. We further found that the disordered defect structure generated by pre-quenching can promote the subsequent quenching regulation, and the minimization of particle size was more sensitive to quenching and thus was regulated as a whole, overcoming the thermodynamic bottleneck. The NiMoO4/NiFe2O4 heterostructured nanocatalyst demonstrated remarkable catalytic activity for oxygen evolution and reduction reactions in alkaline media, thus delivering excellent electrochemical performance in rechargeable zinc-air batteries. Our finding provided a novel inspiration for the preparation of highly active heterostructured metal oxide nanocatalysts, which can be applied to various oxides, such as CoMoO4/CoFe2O4.

Metal-oxygen bonds significantly affect the oxygen reaction kinetics of metal oxide-based catalysts but still face the bottlenecks of limited cognition and insufficient regulation. Herein, we develop a unique strategy to accurately tailor metal-oxygen bond structure via amorphous/crystalline heterojunction realized by ion-exchange. Compared with pristine amorphous CoSnO3-y, iron ion-exchange induced amorphous/crystalline structure strengthens the Sn-O bond, weakens the Co-O bond strength, and introduces additional Fe-O bond, accompanied by abundant cobalt defects and optimal oxygen defects with larger pore structure and specific surface area. The optimization of metal-oxygen bond structure is dominated by the introduction of crystal structure and further promoted by the introduction of Fe-O bond and rich Co defect. Remarkably, the Fe doped amorphous/crystalline catalyst (Co1-xSnO3-y-Fe0.021-A/C) demonstrates excellent oxygen evolution reaction and oxygen reduction reaction activities with a smaller potential gap (ΔE = 0.687 V), and the Zn-air battery based with Co1-xSnO3-y-Fe0.021-A/C exhibits excellent output power density, cycle performance, and flexibility.

To satisfy the increasing power demand for the rapid development of wearable and portable electronics, the design of quasi-solid-state aqueous zinc-ion batteries (QAZIBs) requires the advancement of flexible electrodes possessing excellent electrochemical performance and extraordinary mechanical strength. This purpose could be realized by utilizing electrospinning to obtain flexible film cathodes composed of layer-structured transition metal [email protected] carbon nanofibers ([email protected]), attributed to the synergetic effect between the nanostructured TMDs (for capacity) and interwoven 1D N-CNFs (for flexibility). However, their potentials are seriously impeded by the dissolution and structural instability of active materials during zinc-ion (de)intercalation process, leading to insufficient rate capability and much-shortened cycle life. Herein, to address this big challenge, we have demonstrated the approach of developing an ultrathin Al2O3 coating layer by atomic-layer-deposition (ALD) to greatly boost the electrochemical performance of vanadium diselenide [email protected] (Al2O3@VSe2 [email protected]) film cathode in flexible QAZIBs. Moreover, the ALD-Al2O3 nanocoating provides desperately necessary mechanical robustness in the cross-2D nanosheet direction of VSe2 standing on the N-CNFs surface, as confirmed by finite element simulation results. Consequently, the QAZIB delivers an outstanding stack energy density of ∼125 Wh kg⁻¹, an ultrahigh rate capability of 65.2% capacity retention after 200-fold increase in current density and an excellent cycling performance of 86.2% retention after 2500 cycles. Finally, we integrate the flexible QAZIB into a soft inchworm robot, which achieves reversible actuation both on land and in water and keeps good electrochemical stability, showing the prospective potentials of introducing energy storage devices for soft robotics with broad multifunctional applications.

Currently there is tremendous interest in supported metal single atom (MSA) materials owing to their remarkable performance in many fields. Typically MSA materials are prepared by co-precipitation or pyrolysis methods, and can be highly variable in terms of the spatial distribution of MSA sites created. Herein, we report a new method, quenching, as an effective synthetic strategy for loading MSA sites onto nanostructured supports. As a proof of concept, a hot α-Fe2O3@CNT fiber (CNT = carbon nanotube) was quenched rapidly by immersion in an aqueous solution of SnCl4 at 4 °C, to yield a fiber uniformly decorated with Sn single atoms (Sn-Fe2O3@CNT fiber). The resulting Sn-Fe2O3@CNT fiber electrode exhibits outstanding performance, offering a capacitance of 391.32 mF cm⁻² at 0.24 mA cm⁻², which is more than 1.5 times that of the α-Fe2O3@CNT fiber. Moreover, an all-solid-state fiber-shaped supercapacitor consisting of a Sn-Fe2O3@CNT fiber negative electrode and a MnO2@CNT fiber positive electrode affords a very high areal capacitance of 105.68 mF cm⁻² and an exceptional energy density of 6.09 mW h cm⁻³. The surface quenching strategy is expected to be widely applicable for the synthesis of MSA functionalized materials, thus opening up new avenues for energy and catalysis research.

High voltage cathodes are necessary for improving energy density of electrochemical energy storage devices, but face issues originated from the instable interface between cathodes and electrolytes. In this work, we report a novel strategy to enforce the interface stability of high voltage cathode by architecting an efficiently protective interphase via simply one-step treating the cathode materials with polymers. A representative high voltage cathode, lithium/manganese-rich oxide (LMR), is considered with a match of a polymer, aromatic polyamide (APA). Electrochemical measurements combining with physical characterizations and theoretical calculations demonstrate that a thin but robust interphase of 5 nm thick is successfully architected on LMR and consequently the cycling performances of LMR are significantly improved. This strategy is facile but efficient and therefore helpful for the application of high voltage cathodes in large scale.

Lithium metal, as an ideal anode material for rechargeable and high energy density batteries, suffers from the inherent limitations of sensitivity to dendrite growth and the humid atmosphere. Here, a bifunctional composite interphase is designed to settle these issues. The interphase which is generated on the surface of Li foil through electroless plating with a solution of aluminum fluoride can guide uniform Li plating/stripping behaviors with reduced overpotential and simultaneously improve moisture resistance. Owing to the unique feature, the assembled cells with the protectedanode and a LiFePO4 cathode exhibit long cycle life (>300 cycles) with an extraordinary capacity retention (>95%). Further, even the protectedanodes are exposed to humid air (25% relative humidity) for over 24 h, the cells still achieve outstanding performance, comparable to those without exposure. This work thus provides a promising approach towards dendrite-free and air-stable lithium metal batteries.