As the application of next-generation energy storage systems continues to expand, rechargeable secondary batteries with enhanced energy density and safety are imperative for energy iteration. Sodium-ion batteries (SIBs) have attracted extensive attention and are recognized as ideal candidates for large-scale energy storage due to the abundant sodium resources and low cost. Sodium metal anodes (SMAs) have been considered as one of the most attractive anode materials for SIBs owing to their high specific capacity (1166 mAh g−1), low redox potential, and abundant natural resources. However, the uncontrollable dendrite growth and inevitable side reactions on SMA lead to the continuous deterioration of the electrochemical performance, causing serious safety concerns and limiting their practical application in the future. Therefore, the construction of stable dendrite-free SMAs is a pressing problem for advanced sodium metal batteries (SMBs). In this review, we comprehensively summarize the research progress in suppressing the formation of sodium dendrite, including artificial solid electrolyte interphase (SEI), liquid electrolyte modification, three-dimensional (3D) host materials, and solid-state electrolyte. Additionally, key aspects and prospects of future research directions for SMAs are highlighted. We hope that this timely review can provide an overall picture of sodium protection strategies and stimulate more research in the future.
Biomass-derived carbon has demonstrated great potentials as advanced electrode for capacitive deionization (CDI), owing to good electroconductivity, easy availability, intrinsic pores/channels. However, conventional simple pyrolysis of biomass always generates inadequate porosity with limited surface area. Moreover, biomass-derived carbon also suffers from poor wettability and single physical adsorption of ions, resulting in limited desalination performance. Herein, pore structure optimization and element co-doping are integrated on banana peels (BP)-derived carbon to construct hierarchically porous and B, N co-doped carbon with large ions-accessible surface area. A unique expansion-activation (EA) strategy is proposed to modulate the porosity and specific surface area of carbon. Furthermore, B, N co-doping could increase the ions-accessible sites with improved hydrophilicity, and promote ions adsorption. Benefitting from the synergistic effect of hierarchical porosity and B, N co-doping, the resultant electrode manifest enhanced CDI performance for NaCl with large desalination capacity (29.5 mg g−1), high salt adsorption rate (6.2 mg g−1 min−1), and versatile adsorption ability for other salts. Density functional theory reveals the enhanced deionization mechanism by pore and B, N co-doping. This work proposes a facile EA strategy for pore structure modulation of biomass-derived carbon, and demonstrates great potentials of integrating pore and heteroatoms-doping on constructing high-performance CDI electrode.
Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years, we developed two sustainable routes (i.e., the impregnation method and the one-pot synthesis) to prepare the hydrochar-supported catalysts and tested its catalytic performance on the reductive amination. Several techniques, such as TEM, XRD and XPS, were adopted to characterize the structural and catalytic features of samples. Results indicated that the impregnation method favors the formation of outer-sphere surface complexes with porous structure as well as well-distributed metallic nanoparticles, while the one-pot synthesis tends to form the inner-sphere surface complexes with relatively smooth appearance and amorphous metals. This difference explains the better activity of catalysts prepared by the impregnation method which can selectively convert benzaldehyde to benzylamine with an excellent yield of 93.7% under the optimal reaction conditions; in contrast, the catalyst prepared by the one-pot synthesis only exhibits a low selectivity near to zero. Furthermore, the gram-scale test catalyzed by the same catalysts exhibits a similar yield of benzylamine in comparison to its smaller scale, which is comparable to the previously reported heterogeneous noble-based catalysts. More surprisingly, the prepared catalysts can be expediently recycled by a magnetic bar and remain the satisfying catalytic activity after reusing up to five times. In conclusion, these developed catalysts enable the synthesis of functional amines with excellent selectivity and carbon balance, proving cost-effective and sustainable access to the wide application of reductive amination.
Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant remediation. Embracing the recent advance in photothermal technology, a functional sponge was prepared by coating a sodium alginate (SA) impregnated sponge with a surface layer of reduced graphene oxide (rGO) to act as a photothermal conversion medium and then subsequently evaluated for its ability to enhance Pb extraction from contaminated soil driven by interfacial solar evaporation. The SA loaded sponge had a Pb adsorption capacity of 107.4 mg g−1. Coating the top surface of the SA sponge with rGO increased water evaporation performance to 1.81 kg m−2 h−1 in soil media under one sun illumination and with a wind velocity of 2 m s−1. Over 12 continuous days of indoor evaporation testing, the Pb extraction efficiency was increased by 22.0% under 1 sun illumination relative to that observed without illumination. Subsequently, Pb extraction was further improved by 48.9% under outdoor evaporation conditions compared to indoor conditions. Overall, this initial work shows the significant potential of interfacial solar evaporation technologies for Pb contaminated soil remediation, which should also be applicable to a variety of other environmental contaminants.
Photocatalysis is an effective way to solve the problems of environmental pollution and energy shortage. Numerous photocatalysts have been developed and various strategies have been proposed to improve the photocatalytic performance. Among them, Bi-based photocatalysts have become one of the most popular research topics due to their suitable band gaps, unique layered structures, and physicochemical properties. In this review, Bi-based photocatalysts (BiOX, BiVO4, Bi2S3, Bi2MoO6, and other Bi-based photocatalysts) have been summarized in the field of photocatalysis, including their applications of the removal of organic pollutants, hydrogen production, oxygen production etc. The preparation strategies on how to improve the photocatalytic performance and the possible photocatalytic mechanism are also summarized, which could supply new insights for fabricating high-efficient Bi-based photocatalysts. Finally, we summarize the current challenges and make a reasonable outlook on the future development direction of Bi-based photocatalysts.
Highly active bifunctional oxygen electrocatalysts accelerate the development of high-performance Zn-air battery, but suffer from the mismatched activities of oxygen evolution reaction (OER) and oxygen reduced reaction (ORR). Herein, highly integrated bifunctional oxygen electrocatalysts, cobalt-tin alloys coated by nitrogen doped carbon (CoSn@NC) are prepared by MOFs-derived method. In this hybrid catalyst, the binary CoSn nanoalloys mainly contribute to highly active OER process while the Co (or Sn)−N−C serves as ORR active sites. Rational interaction between CoSn and NC donates more rapid reaction kinetics than Pt/C (ORR) and IrO2 (OER). Such CoSn@NC holds a promise as air-cathode electrocatalyst in Zn-air battery, superior to Pt/C + IrO2 catalyst. First-principles calculations predict that CoSn alloys can upgrade charge redistribution on NC and promote the transfer to reactants, thus optimizing the adsorption strength of oxygen-containing intermediates to boost the overall reactivity. The tuning of oxygenate adsorption by interactions between alloy and heteroatom-doped carbon can guide the design of bifunctional oxygen electrocatalysts.
Low-cost, flexible and safe battery technology is the key to the widespread usage of wearable electronics, among which the aqueous Al ion battery with water-in-salt electrolyte is a promising candidate. In this work, a flexible aqueous Al ion battery is developed using cellulose paper as substrate. The water-in-salt electrolyte is stored inside the paper, while the electrodes are either printed or attached on the paper surface, leading to a lightweight and thin-film battery prototype. Currently, this battery can tolerate a charge and discharge rate as high as 4 A g−1 without losing its storage capacity. The charge voltage is around 2.2 V, while the discharge plateau of 1.6–1.8 V is among the highest in reported aqueous Al ion batteries, together with a high discharge specific capacity of ∼140 mAh g−1. However, due to the water electrolysis side reaction, the faradaic efficiency can only reach 85% with a cycle life of 250 due to the dry out of electrolyte. Benefited from using flexible materials and aqueous electrolyte, this paper-based Al ion battery can tolerate various deformations such as bending, rolling and even puncturing without losing its performance. When two single cells are connected in series, the battery pack can provide a charge voltage of 4.3 V and a discharge plateau as high as 3–3.6 V, which are very close to commercial Li ion batteries. Such a cheap, flexible and safe battery technology may be widely applied in low-cost and large-quantity applications, such as RFID tags, smart packages and wearable biosensors in the future.
Emerging excessive greenhouse gas emissions pose great threats to the ecosystem, which thus requires efficient CO2 capture to mitigate the disastrous issue. In this report, large molecular size bisphenol A ethoxylate diacrylate (BPA) was employed to crosslink poly (ethylene glycol) methyl ether acrylate (PEGMEA) via the green and rapid UV polymerization strategy. The microstructure of such-prepared membrane could be conveniently tailored by tuning the ratio of the two prepolymers, aiming at obtaining the optimized microstructures with suitable mesh size and PEO sol content, which was approved by a novel low-field nuclear magnetic resonance technique. The optimum membrane overcomes the trade-off challenge: dense microstructures lower the gas permeability while loose microstructures lower high-pressure-resistance capacity, realizing a high CO2 permeability of 1711 Barrer and 100-h long-term running stability under 15 atm. The proposed membrane fabrication approach, hence, opens a novel gate for developing high-performance robust membranes for CO2 capture.