Linfeng Fei

Current demands for recycling retired cathode materials and developing high-energy-density lithium-ion batteries inspire the possible conversion of end-of-life LiCoO2 (LCO) streams into next-generation high-voltage cathode materials. In this work, we demonstrate a one-step approach that upcycles degraded LCO materials by synergistically combining Mg/Al dual-doping with Li3PO4 surface engineering for stable high-voltage applications. The product demonstrates exceptional electrochemical performance up to 4.6 V, delivering 211.7 mAh g–1 at 0.1 C with outstanding cycling stability (98.56% and 80.21% capacity retention after 200 and 500 cycles at 1 C, respectively), far exceeding that of commercial LCO material (75.52% after 200 cycles); the superiority stems from the synergistic bulk-surface modification that simultaneously suppresses phase transitions and interfacial degradation during electrochemical operations. This work provides a transformative pathway for unlocking the high-voltage potential of LCO from degraded materials while demonstrating that rational material engineering well aligns environmental sustainability with enhanced electrochemical performance.

The disorder–order transition of metal alloys delivers ordered intermetallic nanoparticles (NPs) as efficient and stable catalysts. However, this transition is practically challenging due to the thermodynamically low driving force and the complex kinetic competition with concurrent processes (e.g., phase separation). Here, we report a kinetic-controlled phase-capturing strategy for ordering multimetallic NPs via pulsed heating treatment. This strategy enables the rapid and universal synthesis of intermetallic NPs with varying elemental compositions (up to eight elements) and stoichiometric ratios in seconds (<10 pulses, down to 1 pulse). In situ transmission electron microscopy reveals a multistep transformation pathway, where disordered NPs premelt at the heating stage of each pulse and subsequently recrystallize toward metastable intermediate states or the final ordered structures via short-range atomic diffusion in the cooling stage. This work develops a promising concept for controllably synthesizing complex intermetallic NPs, as well as for obtaining versatile metastable structures in nanomaterials.

Aerogels based on pliable nanomaterials hold great potential for diverse applications. Herein, a bifunctional reduced graphene oxide-bridged MXene (rGM) aerogel with vertically aligned channels is fabricated via a facile directional freezing and mild thermal annealing strategy. This architectural design effectively mitigates the restacking and oxidation issues of MXene while optimizing its synergistic performance for solar evaporation and electromagnetic interference (EMI) shielding. The rGM aerogel thereby exhibits exceptional sunlight absorption (~96.2%), superior wettability, and efficient photothermal conversion. As a solar evaporator, it achieves a high evaporation rate of 2.62 kg m−2 h−1 and an energy efficiency of 91.68% under 1 sun illumination. Moreover, the synergistic conductive loss and multiple internal reflections within the aerogel deliver an outstanding EMI shielding effectiveness of 35.67 dB in the X-band (8.2−12.4 GHz). This work provides a versatile strategy for designing advanced aerogels that integrate efficient solar-thermal conversion with high-performance EMI shielding, opening promising avenues for multifunctional aerogel materials.

Spent LiCoO ₂ (S‐LCO) cathode materials from retired lithium‐ion batteries (LIBs) pose severe environmental threats and represent a noteworthy waste of strategic resources. The emerging regeneration/upcycling approach for S‐LCO mainly adopts solid‐state treatment, showing significant potential of short‐range, high‐efficient reactivation of S‐LCO materials. Yet it suffers from the complex pre‐determination of lithium content as well as the varying degradation degrees of S‐LCO materials from different batches of retired LIBs. Meanwhile, the cost‐effective ternary layered oxides have become the mainstream cathode materials for LIBs due to the rapid popularization of electric vehicles. Herein, we use a LiOH‐LiNO ₃ eutectic molten salt as the reaction medium to upcycle S‐LCO for single‐crystalline LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (NCM111) cathode materials. The molten salt treatment not only achieves self‐saturating relithiation and direct transformation of S‐LCO toward stoichiometric NCM111 materials but also rejuvenates the product with structural and compositional integrity for outstanding electrochemical performance. The product delivers a specific capacity of 161.6 mAh g ⁻¹ at 0.1 C and a 92.4% capacity retention after 200 cycles at 1 C, outperforming those of commercial NCM111 materials. This study provides a simple, green, and scalable approach for handling those S‐LCO materials, suggesting a sustainable and transformative solution for recycling retired LIBs.

A surprising tribocatalytic capability has been discovered for Si single crystals to convert mechanical energy into chemical energy for organic dye degradation recently. In this study, their tribocatalytic capability has been explored for converting mechanical energy into chemical energy of water splitting. In glass reactors with Si single crystals coated on the bottoms and with H₂O and N₂ enclosed, Al₂O₃ nanoparticles, TiO₂ nanoparticles, and NiO particles were stimulated through magnetic stirring using home-made PTFE magnetic rotary disks separately. For Al₂O₃ nanoparticles, as much as 14,330 and 41,964 ppm H₂ were produced after 1 and 3 h of 400 rpm magnetic stirring, respectively, much higher than those obtained for TiO₂ and NiO, and for Al₂O₃ nanoparticles in glass-bottomed reactors as well. The tribocatalytic production of H₂ was further explored with respect to NaCl addition to H₂O and p/n doping in Si, with negative effects observed for them all. Photoluminescence spectroscopy revealed continuous generation of hydroxyl radicals in the course of magnetic stirring, which supports a tribocatalytic mechanism based on the excitation of electron–hole pairs in Si single crystals through mechanical energy absorbed through friction. These findings suggest a great potential for narrow-band semiconductors to utilize mechanical energy through friction to carry out important chemical reactions.

LiCoO₂ (LCO) materials always undergo an irreversible phase transition from the original layered phase (LP) to the electrochemically inert spinel phase (SP) during cycling that severely degrades their performance in lithium-ion batteries. Consequently, the relithiation of SP phase in degraded LCO, or in other words, the reverse SP-to-LP phase transition, is of urgent importance for the community. Herein, we investigate the feasibility and mechanism of thermal-induced relithiation and SP-to-LP transition in LCO. It is revealed that this phase transition occurs at a mild temperature region (∼300 °C). Moreover, the results from combined in situ/ex situ characterization suggest that the SP-to-LP phase transition follows a “nucleation–oscillation–aggregation” mechanism, which showcases a strong anisotropic characteristic while propagating from the surface toward the bulk of particles. These findings provide profound insights into the SP-to-LP phase transition and lay a solid scientific foundation for developing advanced synthesis and regeneration strategies in layered oxide cathodes.

Layered MXenes have garnered attention as promising anode materials for lithium-ion batteries (LIBs) due to their high electrical conductivity, tunable interlayer spacing, and versatile surface functional groups. However, the practical applications are greatly impeded by sluggish ion transport kinetics, primarily resulting from the issue of self-restacking and the presence of strong electronegative surface terminations. Herein, we simultaneously address these challenges by anchoring zirconium atomic clusters (Zr ACs) onto MXene nanosheets via a wet-chemical approach. The optimized material exhibits a high specific capacity of 588.6 mAh g-¹ at 0.1 A g-¹ (over three times than that of pristine MXene) along with outstanding rate capability (191.6 mAh g-¹ at 2 A g-¹) and cycling stability (an average capacity decay of ~0.10% per cycle over 1000 cycles). Notably, it even retains a capacity of 75.4 mAh g-¹ at 0.2 A g-¹ over 100 cycles at −10 °C. Combined experimental and theoretical analyses reveal that Zr ACs not only expand the interlayer spacing of MXene nanosheets but also modulate the surface termination chemistry, thereby enhancing reversible Li⁺ adsorption and surface pseudocapacitance. This work underscores a tunable strategy to balance surface chemistry and interlayer structure of MXenes, pushing their applications forward in high-performance energy storage systems.

The emergence of the flexoelectric effect (i.e., the linear electromechanical coupling between strain gradient and charge polarization) in a wide range of materials suggests a new catalytic mechanism in mechanocatalysis for activating chemical bonds and reactions. This review comprehensively summarizes the recent developments of flexoelectric catalysis, including its theoretical foundations, experimental breakthroughs, and advanced materials. It commences with the brief history and underlying mechanisms of flexoelectricity and flexoelectric catalysis. Then, the recent strategies for improving the performance of flexoelectric catalysts are reviewed. Subsequently, multi-field coupling strategies that can be used to achieve superior performance are discussed. Finally, the prevailing technical challenges together with the future directions are outlined, positing that flexoelectric catalysis is poised to bridge fundamental materials science with scalable clean energy solutions.

The carboxybetaine oligomer, showing strong interactions with water/Zn ²⁺ /Zn, achieves overall regulation from the bulk electrolyte to the anode interface, thereby suppressing side reactions and optimizing Zn deposition in aqueous zinc-ion batteries.

Supported metal nanoparticles always experience thermal-induced sintering that severely depresses their catalytic performance and durability. Recently, ultrafast heating technology has been widely adopted in synthesizing diverse metal nanoparticles or even single atoms on supporting materials, offering enhanced anti-sintering capabilities compared to conventional heating protocols. However, the mechanisms and kinetics underlying this anti-sintering behavior during ultrafast heating processes remain poorly understood. Here, using in situ scanning transmission electron microscopy and theoretical analysis, we microscopically reveal a metastable state for supported metal nanoparticles induced by ultrafast heating pulses, which significantly mitigates the thermal-induced sintering while effectively improves the crystallization degree of metal nanoparticles together with the metal/support interfaces. Our results show that Pt nanoparticles supported on graphene flakes are thermodynamically unstable yet kinetically stable across the ultrafast heating pulses; as a consequence, the Pt/graphene interface is gradually optimized in a lattice scale, leading to remarkable sintering resistance for Pt nanoparticles. These atomic-scale insights provide thorough fundamental understandings for ultrafast heating in stabilizing metal nanoparticles and may further guide the high-throughput production of robust supported metal nanocatalysts.