Exploration of the Performance and Mechanism of Uranium Adsorption by a Covalent Organic Framework Possessing the Thiazole Structure.

This study prepared an active 2-D covalent organic skeleton (HDU-27) with a network structure, high crystallinity, considerable specific surface area, excellent pore structure, and excellent stability. Kinetic studies manifested that HDU-27 could effectively capture uranium as monolayer chemisorption within a very short kinetic equilibrium time (10 min). In particular, the temperature significantly and positively impacted the uranium adsorption performance of HDU-27. At 298, 313, and 328 K, the adsorption capacity reached 269.2, 488.8, and 576.2 mg g-1, respectively, suggesting the potential to treat high-temperature industrial wastewater containing uranium. HDU-27 had high stability and recoverability with an adsorption efficiency of 98.5% after five adsorption-desorption cycles. According to X-ray photoelectron spectroscopy, the mechanism of interaction between U(VI) and HDU-27 was mainly the chelation of UO22+ by the N atom in the thiazole structure and the strong coordination of the O atom in the keto structure with UO22+. More excitingly, HDU-27 could chemically reduce soluble U(VI) to insoluble U(IV) and release binding sites for the adsorption of additional U(VI). In conclusion, HDU-27 has outstanding potential for uranium adsorption from industrial wastewater containing uranium.

Significant Strain Dissipation via Stiff-Tough Solid Electrolyte Interphase Design for Highly Stable Alloying Anodes.

The pulverization of alloying anodes significantly restricts their use in lithium-ion batteries (LIBs). This study presents a dual-phase solid electrolyte interphase (SEI) design that incorporates finely dispersed Al nanoparticles within the LiPON matrix. This distinctive dual-phase structure imparts high stiffness and toughness to the integrated SEI film. In comparison to single-phase LiPON film, the optimized Al/LiPON dual-phase SEI film demonstrates a remarkable increase in fracture toughness by 317.8 %, while maintaining stiffness, achieved through the substantial dissipation of strain energy. Application of the dual-phase SEI film on an Al anode leads to a 450 % enhancement in cycling stability for lithium storage in dual-ion batteries. A similar enhancement in cycling stability for silicon anodes, which face severe volume expansion issues, is also observed, demonstrating the broad applicability of the dual-phase SEI design. Specifically, homogeneous Li-Al alloying has been observed in conventional LIBs, even when paired with a high mass loading LiNi0.5 Co0.3 Mn0.2 O2 cathode (7 mg cm-2 ). The dual-phase SEI film design can also accelerate the diffusion kinetics of Li-ions through interface electronic structure regulation. This dual-phase design can integrate stiffness and toughness into a single SEI film, providing a pathway to enhance both the structural stability and rate capability of alloying anodes.

Unusual Size Effect in Ion and Charge Transport in Micron-Sized Particulate Aluminum Anodes of Lithium-Ion Batteries.

Aluminum is a promising anode material for lithium-ion batteries owing to its high theoretical capacity, excellent conductivity, and natural abundance. An anomalous size effect was observed for micron-sized aluminum powder electrodes in this work. Experimental and theoretical investigations reveal that the insulating oxide surface layer is the underlying cause, which leads to poor electrical conductivity and limited capacity utilization when the particle is too small. Additionally, poor electrolyte wettability also accounts for the hindered reaction kinetics due to the weak polarity feature of the oxide layer. Surface grafting of polar amino groups was demonstrated to be an effective strategy to improve electrolyte wettability. The present work revealed the critical limitations and underlying mechanisms for the aluminum anode, which is crucial for its practical application. Our results are also valuable for other metallic anodes with similar issues.

In Situ Chemical Lithiation Transforms Diamond-Like Carbon into an Ultrastrong Ion Conductor for Dendrite-Free Lithium-Metal Anodes.

Lithium (Li)-metal anodes are of great promise for next-generation batteries due to their high theoretical capacity and low redox potential. However, Li-dendrite growth during cycling imposes a tremendous safety concern on the practical application of Li-metal anodes. Herein, an effective approach to suppress Li-dendrite growth by coating a polypropylene (PP) separator with a thin layer of ultrastrong diamond-like carbon (DLC) is reported. Theoretical calculations indicate that the DLC coating layer undergoes in situ chemical lithiation once assembled with the lithium-metal anode, transforming the DLC/PP separator into an excellent 3D Li-ion conductor. This in situ lithiated DLC/PP separator can not only mechanically suppress Li-dendrite growth by its intrinsically high modulus (≈100 GPa), but also uniformly redistributes Li ions to render dendrite-free lithium deposition. The twofold effects of the DLC/PP separator result in stable cycling of lithium plating/stripping (over 4500 h) at a high current density of 3 mA cm-2 . Remarkably, this approach enables more than 1000 stable cycles at 5 C with a capacity retention of ≈71% in a Li || LiFePO4 coin cell and more than 200 stable cycles at 0.2 C in a Li || LiNi0.5 Co0.3 Mn0.2 O2 pouch cell with cathode mass loading of ≈9 mg cm-2 .