Yanjie Hu

Lithium squarate (Li2C4O4) is a high-capacity cathode prelithiation additive, but its full decomposition voltage (∼4.5 V) induces severe side reactions, necessitating a reduction to 4.2 V for Ni-rich cathodes. This study prepares a carbon-composited Li2C4O4 prelithiation additive and investigates the impact of a 4.2 V potentiostatic activation protocol on its decomposition efficiency, interface evolution, and cell performance. A 24 h potentiostatic step at 4.2 V enables nearly complete decomposition of the additive in half cells, with a first-cycle charge capacity 64.78% higher than under galvanostatic activation. In NCM811 half cells, 100% decomposition is achieved under 4.2 V potentiostatic activation, comparable to 4.5 V galvanostatic activation, while forming a denser cathode-electrolyte interphase (CEI) that reduces impedance and suppresses side reactions. These half cells show 4.76% higher capacity retention after 150 cycles at 1C and deliver 114 mAh g–1 at 10C. Pouch full-cell tests confirm improved additive decomposition and optimized interphases, raising capacity retention to 92.6% after 150 cycles. This study demonstrates that 4.2 V potentiostatic activation enables efficient prelithiation without high voltage side reactions, providing experimental and theoretical support for industrial applications in Ni-rich ternary systems.

Steering CO₂ photoreduction toward C₂ hydrocarbons remains challenging because of the sluggish multielectron/proton-transfer kinetics and the high energetic demand for C-C coupling. Herein, we report a flame-spray-pyrolysis strategy to construct Au-CeO_x nanostructures featuring coexisting symmetric oxygen vacancies (Ce-O_v-Ce) and symmetry-broken oxygen vacancy (Au-O_v-Ce) motifs at the Au-CeO_x interface. The symmetric Ce-O_v-Ce sites provide favorable adsorption environments for CO₂ activation, whereas the symmetry-broken Au-O_v-Ce sites induce interfacial electron redistribution and promote electron enrichment. The cooperative interaction between these two vacancy configurations shifts the reaction route from *CO desorption toward deep hydrogenation and *CH₃-mediated C-C coupling. As a result, the optimized Au-CeO_x-SAO_v catalyst achieves a C₂H₆ production rate of 2581 μmol g_Au^-1 h^-1 with a selectivity of 88.14% and an electron utilization rate of 41.22 mmol g_Au^-1 h^-1 in photocatalytic CO₂ reduction with H₂O. Mechanistic studies suggest that the symmetry-broken Au-O_v-Ce sites stabilize hydrogenated C₁ intermediates and lower the energetic requirement for coupling two *CH₃ species. This work establishes symmetry-differentiated oxygen-vacancy engineering as an effective strategy for directing multielectron CO₂ photoreduction toward C₂ hydrocarbons.

Conventional TiO2 photocatalysts are constrained by limited solar-light utilization and poor selectivity, which severely hinder their application in antibiotic wastewater treatment. Herein, we construct a Yb/Nd co‑doped TiO2@molecularly imprinted polymer (YNT@MIP) system that integrates near‑infrared upconversion luminescence with selective recognition to boost tetracycline (TC) degradation. Flame spray pyrolysis is employed to incorporate Yb3+ and Nd3+ ions, followed by interfacial coupling with a MIP shell layer, which narrows the apparent band gap to 2.17 eV. Upon 980 nm excitation, upconverted emission in the 465–660 nm range is generated and reabsorbed by TiO2, thereby enhancing charge‑carrier production. The surface MIP shell, anchored via Ti–O–C bonding, provides selective cavities, while its imprinted porous architecture mitigates electron screening and facilitates interfacial charge transfer. The optimized YNT@MIP achieves 93.1% TC degradation within 60 min under simulated sunlight, with a rate constant of 0.042 min–1 and 1.68 times that of the non‑imprinted counterpart, exhibiting a selectivity factor as high as 3.31 in complex water. This synergistic strategy offers a novel viable route toward efficient and selective photocatalytic water purification.

LiMn _x Fe _1‐x PO ₄ (LMFP) olivine cathodes are promising for high‐energy‐density lithium‐ion batteries. Nanosizing particles effectively shortens the Li ⁺ diffusion pathways and sluggish Mn ²⁺ /Mn ³⁺ kinetics severely, but compromises electrode tap density and volumetric performance. We present a materials design strategy that integrates precursor engineering, solvent mediation, and homogeneous doping via flame spray pyrolysis (FSP) to simultaneously overcome these constraints. An organic phosphate ester precursor is employed to induce the formation of a transient molten intermediate phase, enabling surface tension‐driven spheroidization of particles. Concurrently, solvent engineering modulates droplet evaporation kinetics, prolonging high‐temperature residence time to ensure complete crystallization. The inherent rapid mixing and quenching of FSP ensure atomic‐scale homogeneity, which we leverage to implement element co‐doping that enhances bulk ion/electron transport. The synergistic effects of these properties enable the optimized LMFP cathode to achieve an exceptional electrode‐level volumetric energy density of 1145–1317 Wh L ⁻¹ . It also delivers a high initial capacity of 155.4 mAh g ⁻¹ at 0.1 C and 135 mAh g ⁻¹ at 5 C, retaining 97.6% capacity after 1000 cycles at 1 C. This work demonstrates that FSP is a versatile platform for designing electrode materials, simultaneously tackling the intertwined challenges of kinetics and density, and provides a viable pathway toward practical high‐energy batteries.

Strong CO adsorption on platinum surfaces at low temperatures remains a critical bottleneck for the stability of emission control catalysts. While oxygen vacancy engineering can modulate metal–support interactions, conventional symmetric vacancies (Ce ^{3 +} –O _v –Ce ^{3 +} ) often suffer from poor structural durability and uniform charge distribution, which inherently limits their ability to dynamically regulate electronic states. Herein, a rapid one‐step strategy utilizing hydrogen‐quenching flame spray pyrolysis is developed to construct asymmetric Pt–Ov–Ce interfaces. Unlike symmetric defects, this engineered asymmetric configuration disrupts local charge symmetry, creating a built‐in electric field that acts as a directional electron channel to drive electron transfer from Pt to the ceria support. This spatial electronic reconstruction simultaneously reduces the electron density of Pt sites, significantly weakens the Pt–CO bond, thereby alleviating the poisoning of active sites and enriching interfacial vacancies, promoting the rapid activation of O ₂ . Consequently, the asymmetric catalyst achieves 90% CO conversion at 180°C, which is 46°C lower than conventional counterparts, and maintains exceptional stability with negligible activity loss over 1000 min. This study provides a fundamental understanding of local charge asymmetry in defect engineering and demonstrates the potential of millisecond flame quenching for designing highly poison‐resistant catalysts.