Ang, Edison Huixiang

The effective recycling of retired LiFePO4 batteries serves dual purposes: addressing the resource supply-demand contradiction and mitigating environmental pollution. However, the existing recycling methods for waste LiFePO4 batteries often entail high energy consumption, time consumption, complex procedures, or the use of substantial amounts of chemical raw materials, leading to increased recycling costs. Moreover, both methods generate toxic gases or discharge excessive pollutant-containing liquids during the recycling process, posing a risk of secondary pollution. Here, we introduce the application of ultrasound-assisted regeneration in waste LiFePO4 cathode material directly. Ultrasound waves generate localized high temperature, high pressure, and intense shock wave jets to repair the lithium vacancy defects and anti-site defects in the waste LiFePO4. Based on the experimental findings, the regeneration of LiFePO4 was achieved with impressive results. At an ultrasound power of 500 W and a duration of 50 min, the regenerated LiFePO4 displayed a discharge specific capacity of 135.1 mAh∙g−1 and an impressive capacity retention of 97 % after 100 cycles at a 1C (1C = 170 mA g−1) current density. This study presents a promising and environmentally friendly approach for recycling and regenerating retired LiFePO4 batteries.

Lithium/fluorinated-carbon (Li/CFx) primary batteries are widely used in defense and military fields due to their stable discharge plateau, low self-discharge rate, and adaptability across a wide temperature range. However, enhancing their overall energy density and discharge capacity at low temperatures remains a critical challenge. Herein, we report a strategically designed LiBF4-based sulfite/carboxylate electrolyte, where the anion-involved solvation structure significantly enhances electrochemical kinetics by reducing the desolvation barrier. Simultaneously, it introduces a radical reaction mechanism that contributes to additional capacity. As a result, the Li/CFx primary batteries with this formulated electrolyte deliver a specific capacity of 2,257.15 mAh g−1 at 25 °C. More importantly, when operating at −40 °C, the batteries exhibit an exceptionally high discharge capacity of 1,549.4 mAh g−1 and an energy density of 2,868.6 Wh kg−1. Even at −60 °C, the Li/CFx cells achieve a specific capacity of 444.3 mAh g−1 and an energy density of 821.8 Wh kg−1 at 0.1 C, significantly outperforming previously reported organic-based liquid electrolytes. This work offers a viable strategy for enhancing the specific capacity and energy density of primary batteries in extreme environments, providing valuable insights for future developments.

Photothermal catalysis of functional materials triggered by light-irradiation to local heating approach attracts growing attention, but one key detail affecting catalytic thermodynamic process was often ignored that thermal-conductive surface of functional materials directly contacting reaction solution easily delivers heat to the reaction system, leading to weakening heating effect in the interfacial local catalytic microenvironment. Herein, a functional low-thermal-conductivity layer that Mn-coupling porous SiO2 shell layer was constructed over the Co3O4 nanospheres. Specifically, SiO2 with porous channels introduced acts as the thermal-insulation layer to prevent the heat dissipation of the photo-heating core of Co3O4. More importantly, porous channel and inserted MnOx active species could further offer an additive special reaction microenvironment over the photo-heating core of Co3O4. Additionally, the introduction of Mn and structural remodeling through tailored annealing temperature (600–800 °C) can give improved catalytic hybrids abundant valence states and interfacial effects. A series of Co@Mn/m-SiO2 catalysts were fabricated based on the above control tactic. The Co@Mn/m-SiO2 catalysts exhibit superior activating ability for peroxymonosulfate (PMS) to degrade bisphenol A (BPA) and other pollutants including 2, 4-dichlorophenol (2, 4-DCP), phenol (PhOH), oxytetracycline (OTC), and tetracycline (TCN). Specifically, Co@Mn/m-SiO2-700 was shown to achieve complete degradation of 20 ppm BPA in less than 10 min under optimal conditions. In addition, we demonstrated that functional silica layer modified Co3O4 affords a better photo-heating effect compared to bare Co3O4 sphere in air or water, thereby contributing to a faster PMS activation efficiency. Besides, thermal treatment processing for Co@Mn/m-SiO2 catalyst makes the surface reactive species be optimized to generate more beneficial redox pairs and reach excellent photothermal catalytic efficiency in various pollutants treatment.

Sodium-ion batteries (SIBs) are emerging as an alternative to lithium-ion batteries (LIBs) in the fields of medium and large-scale stationary energy storage due to the sufficient natural abundance and low cost of sodium resources. The enhanced electrochemical performance of electrode materials is desired to accelerate the development of SIB systems in order to meet the increased need for practical use. Vanadium chalcogenides (VCs), featuring with high capacity and excellent redox reversibility, are considered to be the promising candidates for SIB anodes. This review discusses the recent advances and the remaining intrinsic challenges in VCs, covering an overview of the various synthesis methods, modifying strategies and electrochemical performance. In addition, the perspectives for future research are also provided based on current progress and scientific understanding.

Ion selective separations play crucial roles in the fields of energy storage, pollution management, and industrial processes, etc. Ion exchange membranes (IEMs) offer promise for these separations but often lacking the required selectivity. In this work, we have developed a kind of IEM based on metal-organic frameworks (MOFs) to enhance membrane separation performance for electrodialysis (ED). Specifically, for poly(arylene ether sulfone)-based anion exchange membranes (AEMs), we introduced the modified MOFs through doping to create a transport pathway for target ions, leveraging their precise size-based separation effects. This approach significantly improves ion selectivity. Remarkably, at a current density of 2.5 mA·cm⁻², the monovalent ion selectivity (Cl−/SO₄²⁻) of PAES-UIO-66-Pyr could reach 54.26, while the monovalent ion selectivity (NO₃⁻/SO₄²⁻) could reach 55.90. These enhancements may stem from the incorporation of MOF particles, which facilitate the formation of fixed-size channel structures within membrane matrix. These fixed-size channels, coupled with the hydrophobic differences between the original poly(arylene ether sulfone) polymer, created a composite channel system that significantly improved the separation performance for monovalent ions, including Cl−/SO₄²⁻ and NO₃⁻/SO₄²⁻.

The abundant natural resources and low cost benefits of zinc-ion batteries (ZIBs) and potassium-ion batteries (KIBs) offer a better alternative to lithium-ion batteries (LIBs). Nevertheless, the large radius of K+ and high charge density of Zn2+ lead to sluggish electrochemical kinetics and the development of appropriate electrode materials for KIBs and ZIBs is therefore very important. Herein, hierarchical K-doped brookite vanadium dioxide (K–VO2(B)) spheres prepared via a simple microwave-assisted hydrothermal approach are proposed. K–VO2(B) as an anode material for PIBs shows enhanced electrochemical performance in terms of high capacity (∼420 mA h g−1), exceptional rate capability and long-term cycling performance (500 cycles). For ZIBs, it also achieves a high capacity of 350 mA h g−1 at 500 mA g−1 and 122 mA h g−1 at an extremely high rate of 50 A g−1. The outstanding PIB and ZIB performance of the K–VO2(B) is mainly benefitted from the improved ion diffusion coefficients after K-doping and the occurrence of inherently stable (de)intercalation reactions.

Graphene-based nanomaterials (GBnMs) are currently regarded as a critical building block for the fabrication of membranes for water purification due to their advantageous properties such as easy surface modification of functional groups, adjustable interlayer pore channels for solvent transportation, robust mechanical properties, and superior photothermal capabilities. By combining graphene derivatives with other emerging materials, heteroatom doping and rational design into three-dimensional network can enhance the water transportation and evaporation rates through channels of GBnM laminates and such layered structures have been applied in various water purification technologies. Herein, this minireview summarizes recent progresses on the synthesis of GBnMs and their applications for water treatment technologies, specifically, nanofiltration (NF) and solar desalination (SD). Finally, personal perspectives on the challenges and future directions of this promising nanomaterials are also provided.

With the continuous advancement of electrodialysis (ED) technology, there arises a demand for improved monovalent cation exchange membranes (CEMs). However, limitations in membrane materials and structures have resulted in the low selectivity of monovalent CEMs, posing challenges in the separation of Li+ and Mg2+. In this investigation, a designed CEM with a swelling-embedded structure was created by integrating a polyelectrolyte containing N-oxide Zwitterion into a sulfonated poly(ether ether ketone) (SPEEK) membrane, leveraging the notable solubility characteristic of SPEEK. The membranes were prepared by using N-oxide zwitterionic polyethylenimine (ZPEI) and 1,3,5-benzenetrlcarbonyl trichloride (TMC). The as-prepared membranes underwent systematic characterization and testing, evaluating their structural, physicochemical, electrochemical, and selective ED properties. During ED, the modified membranes demonstrated notable permeability selectivity for Li+ ions in binary (Li+/Mg2+) systems. Notably, at a constant current density of 2.5 mA cm–2, the modified membrane PEI-TMC/SPEEK exhibited significant permeability selectivity (PLi+Mg2+=5.63) in the Li+/Mg2+ system, while ZPEI-TMC/SPEEK outperformed, displaying remarkable permeability selectivity (PLi+Mg2+=12.43) in the Li+/Mg2+ system, surpassing commercial monovalent cation-selective membrane commercial monovalent cation-selective membrane (CIMS). Furthermore, in the Li+/Mg2+ binary system, Li+ flux reached 9.78 × 10–9 mol cm–2 s–1 for ZPEI-TMC/SPEEK, while its Mg2+ flux only reached 2.7 × 10–9 mol cm–2 s–1, showing potential for lithium–magnesium separation. In addition, ZPEI-TMC/SPEEK was tested for performance and stability at high current densities. This work offers a straightforward preparation process and an innovative structural approach, presenting methodological insights for the advancement of lithium and magnesium separation techniques.

The oxygen evolution reaction (OER) is a crucial process in renewable energy technologies, yet it remains hindered by sluggish reaction kinetics, high overpotentials, and poor electron and ion transfer. This study introduces a novel hydrogel-supported electrocatalyst, HFc-NG@PVA, which combines hydrazinocarbonylferrocene-modified nitrogen-doped graphene (HFc-NG) with polyvinyl alcohol (PVA) to enhance OER performance. HFc-NG@PVA exhibited a low overpotential (η10 = 310 mV) and a small Tafel slope (49 mV dec−1), outperforming conventional carbon-based electrodes and approaching the performance of IrO2. Additionally, the hydrogels exhibit excellent mechanical strength, elasticity, and durability, maintaining stable OER performance over 24 h. Mechanistic studies, including density functional theory (DFT) and COMSOL simulation, reveal that the HFc-NG facilitates electron transfer through redox-active HFc, while PVA, a hydrogel, improves ion conduction, hydration, and mechanical support. The integration of HFc-NG into the PVA matrix not only boosts the mechanical and electrochemical properties of the hydrogel but also enhances the stability of the active sites, enabling more efficient OER. The unique hydrogen-bonding network between HFc-NG and PVA further lowers the activation energy for OER, contributing to its superior catalytic efficiency. This work highlights the potential of hydrogel-supported catalysts as promising candidates for efficient, stable, and cost-effective electrocatalysis in energy conversion systems.

Aqueous zinc-ion batteries possess substantial potential for energy storage applications; however, they are hampered by challenges such as dendrite formation and uncontrolled side reactions occurring at the zinc anode. In our investigation, we sought to mitigate these issues through the utilization of in situ zinc complex formation reactions to engineer hydrophobic protective layers on the zinc anode surface. These robust interfacial layers serve as effective barriers, isolating the zinc anode from the electrolyte and active water molecules and thereby preventing hydrogen evolution and the generation of undesirable byproducts. Additionally, the presence of numerous zincophilic sites within these protective layers facilitates uniform zinc deposition while concurrently inhibiting dendrite growth. Through comprehensive evaluation of functional anodes featuring diverse functional groups and alkyl chain lengths, we meticulously scrutinized the underlying mechanisms influencing performance variations. This analysis involved precise modulation of interfacial hydrophobicity, rapid Zn²⁺ ion transport, and ordered deposition of Zn²⁺ ions. Notably, the optimized anode, fabricated with octadecylphosphate (OPA), demonstrated exceptional performance characteristics. The Zn//Zn symmetric cell exhibited remarkable longevity, exceeding 4000 h under a current density of 2 mA cm⁻² and a capacity density of 2 mA h cm⁻². Furthermore, when integrated with a VOH cathode, the complete cell exhibited superior capacity retention compared to anodes modified with alternative organic molecules.