Oxygen Vacancies Boosted Hydronium Intercalation: A Paradigm Shift in Aluminum-Based Batteries.

In aqueous aluminum-ion batteries (AAIBs), the insertion/extraction chemistry of Al3+ often leads to poor kinetics, whereas the rapid diffusion kinetics of hydronium ions (H3O+) may offer the solution. However, the presence of considerable Al3+ in the electrolyte hinders the insertion reaction of H3O+. Herein, we report how oxygen-deficient α-MoO3 nanosheets unlock selective H3O+ insertion in a mild aluminum-ion electrolyte. The abundant oxygen defects impede the insertion of Al3+ due to excessively strong adsorption, while allowing H3O+ to be inserted/diffused through the Grotthuss proton conduction mechanism. This research advances our understanding of the mechanism behind selective H3O+ insertion in mild electrolytes.

Nonreducing Ambient Atmosphere: Pulsed Electric Current Treatment of Co/Ni Doped Perovskite Oxides to Achieve Exsolution Enhanced Electrochemical Performance.

Exsolution of metal nanoparticles (NPs) on the surface of perovskite oxides is a promising approach for developing advanced catalytic materials through a "bottom-up" design strategy. Under a nonreducing ambient atmosphere utilizing pulsed electric current (PEC) treatment to promote the exsolution of perovskite oxides effectively overcomes the limitations inherent in conventional high-temperature vapor phase reduction (HTVPR) in situ exsolution methods. This paper presents the successful synthesis of (La0.7Sr0.3)0.8Ti0.93Ni0.07O3 (LSTN) perovskite oxide and (La0.7Sr0.3)0.8Ti0.93Co0.07O3 (LSTC) perovskite oxide using the sol-gel method, followed by PEC treatment at 600 V, 3 Hz, and 90 s. Utilizing various characterization techniques to confirm that PEC treatment can promote the exsolution of Co and Ni NPs under a nonreducing ambient atmosphere, the results indicated that the exsolved perovskite oxides exhibited significantly improved electrochemical properties. Furthermore, compared to the LSTN-PEC, LSTC-PEC demonstrates a lower onset potential of 1.504 V, a Tafel slope of 87.16 mV dec-1, lower impedance, higher capacitance, superior catalytic activity, and long-term stability.

A novel exsolution technique-twice lasers: rapidly aroused explosive exsolution of nanoparticles to boost electrochemical performance.

The exsolution of nanoparticles (NPs) on material surfaces exhibits good performance with great potential in the field of catalysis. In this study, a method with twice lasers treatment (TLT) is proposed for the first time to rapidly promote the exsolution of Co NPs to the surface of (La0.7Sr0.3)0.93Ti0.93Co0.07O3(LSTC) by laser rapid heating to enhance the electrochemical performance of the LSTC. The entire process from precursor powder-stable perovskite crystal structure-Co NPs exsolution on the LSTC surface takes only ≈36 s by TLT. The Co NPs exsolution was confirmed by x-ray diffractometer, scanning electron microscopy and high-resolution transmission electron microscopy. After TLT, a large number of Co NPs reached 75 particlesµm-2appeared on the surface of LSTC with the onset potential of 1.38 V, the overpotential of 214 mV, and the Tafel slope of 81.14 mV dec-1, showing good catalytic activity and long-term stability. The novel process of using TLT to rapidly induce exsolution of NPs enables the rapid preparation of nanoparticle-decorated perovskite materials with better electrochemical properties, thus enriching exsolution technology and opening a new avenue for surface science research.

A-site deficient La0.52Sr0.28Ti0.94Ni0.06O3by low-pulsed electric current treatment: achieved exsolution of B-site Ni nanoparticles and significant improvement of electrocatalytic properties.

Perovskite materials with exsolved nanoparticles have a wide range of applications in energy conversion systems owing to their unique basal plane active sites and excellent catalytic properties. The introduction of A-site deficiency can help the formation of highly mobile oxygen vacancies and remarkably enhance the reducibility of Ni nanoparticles, thus significantly increasing electronic conductivity and catalytic activity simultaneously. Herein, we adopt pulsed electric current (PEC) treatment, a novel approach instead of the long-time high-temperature reduction technique, and for the first time review that the exsolution of minuscule Ni nanoparticles (8-20 nm) could be facilitated on Ni-doped La0.52Sr0.28Ti0.94Ni0.06O3(LSTN) anodes with A-site deficiency. Encouragingly, finding that low PEC can successfully lead to nanoparticle exsolution and show a significantly improved oxygen evolution reaction performance of LSTN-PEC (LSTN after PEC treatment) possessing A-site deficiency, the onset potential of LSTN-PEC (500 V) (LSTN after PEC treatment with 500 V-4 Hz-90 s) was advanced by 0.173 V, theRctvalue was reduced by 82.38 Ω·cm2, and the overpotential was also reduced by 73 mV.

Pulsed electric current boosts electrochemical performance and electro-conductivity of La x Sr1-x Cr y Ni1-y O3 perovskite via exsolution of nanoparticles.

In situ exsolved nanoparticles (NPs) on surfaces perform well in many catalytic applications. Herein, an emerging technique of pulsed electric current (PEC) for facilitating NPs exsolution was firstly utilized in functional materials towards tailoring structure and morphology of materials. PEC facilitated Ni NPs exsolution in situ and the exposed active sites were highly dispersed on the LaCrO3 substrate surface. Such result was confirmed by combining x-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. As a consequence, PEC-treated and untreated LaCrO3 perovskite samples were employed as electrocatalysts for oxygen evolution reaction (OER). The PEC-treated samples exhibit obviously improved OER activity (lower overpotential, smaller Tafel slope) and lower reaction resistance than the untreated samples. This illustrates that the exsolved Ni NPs driven by PEC are beneficial for the OER performance and are probably the components of the OER active sites.

A strategy for controlling degradation in vitro of carbon fiber-reinforced polylactic acid composites (by combining fiber modification and pulsed electromagnetic fields).

Carbon fiber-reinforced polylactic acid (C/PLA) composites are a human bone-fixation material, but control of the material's degradation remains a major factor hindering its widespread use. In this study, a combined method for controlling the degradation performance in vitro of C/PLA composites was designed. In this strategy, carbon fibers for C/PLA composite reinforcement were prepared in both modified and unmodified forms. A pulsed electromagnetic field (PEF) was then selectively applied during the subsequent degradation process. Results and analysis showed that the interfacial ester bonding between modified carbon fibers and PLA matrices significantly affected degradation in vitro of C/PLA composite. However, PEF affected the degradation performance of C/PLA composites and, after PEF treatment, the material's water absorption, mass retention, and bending and shearing strengths were changed to varying degrees. This method, by combining fiber modification and pulsed electromagnetic fields (abbreviated as CMP) provided a new strategy for the controlled degradation of C/PLA composites in human skeletal fixation.