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Abstract Molecular detection is important in biosensing, food safety, and environmental surveillance. The high biocompatibility, superior mechanical stability, and low cost make plasmon-free surface-enhanced Raman scattering (SERS) a promising sensing technique, the ultrahigh sensitivity of which is urgently pursued for realistic applications. As a proof of concept, we report a mechanochemical strategy, which combines the wrinkling and chemical functionalization, to fabricate a plasmon-free SERS platform based on 2D MnPS3 with a sub-attomolar detection limit. In detail, the formation of wrinkles in 2D MnPS3 enables a SERS substrate of the material to detect trace methylene blue molecules. The mechanism is experimentally revealed that the wrinkled structures contribute to the improvement of light-matter coupling. On this basis, decorating a wrinkled MnPS3 which has absorbed methylene blue with histamine dihydrochloride further lowers the detection limit to 10−19 M. Because the amino groups in histamine dihydrochloride molecules are crosslinkers that create more pathways to promote charge transfer between these substances. This work provides a guidance for the design of SERS sensors with single-molecule-level sensitivity.

Abstract The swift progress in wearable technology has accentuated the need for flexible power systems. Such systems are anticipated to exhibit high efficiency, robust durability, consistent power output, and the potential for effortless integration. Integrating ultraflexible energy harvesters and energy storage devices to form an autonomous, efficient, and mechanically compliant power system remains a significant challenge. In this work, we report a 90 µm-thick energy harvesting and storage system (FEHSS) consisting of high-performance organic photovoltaics and zinc-ion batteries within an ultraflexible configuration. With a power conversion efficiency surpassing 16%, power output exceeding 10 mW cm–2, and an energy density beyond 5.82 mWh cm–2, the FEHSS can be tailored to meet the power demands of wearable sensors and gadgets. Without cumbersome and rigid components, FEHSS shows immense potential as a versatile power source to advance wearable electronics and contribute toward a sustainable future.

Abstract In the last decade, laboratory-scale single-junction perovskite solar cells have achieved a remarkable power conversion efficiency exceeding 26.1%. However, the transition to industrial-scale production has unveiled a significant efficiency gap. The central challenge lies in the difficulty of achieving uniform, high-quality perovskite films on a large scale. To tackle this issue, various innovative strategies for manipulating crystallization have emerged in recent years. Based on an in-depth fundamental understanding of the nucleation and growth mechanisms in large-area perovskite films prepared through blade/slot-die coating methods, this review offers a critical examination of crystallization manipulation strategies for large-area perovskite solar modules. Lastly, we explore future avenues aimed at enhancing the efficiency and stability of large-area PSMs, thereby steering the field toward commercially viable applications.

Abstract Two-dimensional semiconductors with high thermal conductivity and charge carrier mobility are of great importance for next-generation electronic and optoelectronic devices. However, constrained by the long-held Slack’s criteria, the reported two-dimensional semiconductors such as monolayers of MoS2, WS2, MoSe2, WSe2 and black phosphorus suffer from much lower thermal conductivity than silicon (~142 W·m–1·K–1) because of the complex crystal structure, large average atomic mass and relatively weak chemical bonds. Despite the more complex crystal structure, the recently emerging monolayer MoSi2N4 semiconductor has been predicted to have high thermal conductivity and charge carrier mobility simultaneously. In this work, using a noncontact optothermal Raman technique, we experimentally measure a high thermal conductivity of ~173 W·m–1·K–1 at room temperature for suspended monolayer MoSi2N4 grown by chemical vapor deposition. First-principles calculations reveal that such unusually high thermal conductivity benefits from the high Debye temperature and small Grüneisen parameter of MoSi2N4, both of which are strongly dependent on the high Young’s modulus induced by the outmost Si-N bilayers. Our study not only establishes monolayer MoSi2N4 as a benchmark 2D semiconductor for next-generation electronic and optoelectronic devices, but also provides an insight into the design of 2D materials for efficient heat conduction.

Abstract Sustainable battery recycling is essential for achieving resource conservation and alleviating environmental issues. Many open/closed-loop strategies for critical metal recycling or direct recovery aim at a single component, and the reuse of mixed cathode materials is a significant challenge. To address this barrier, here we propose an upcycling strategy for spent LiFePO4 and Mn-rich cathodes by structural design and transition metal replacement, for which uses a green deep eutectic solvent to regenerate a high-voltage polyanionic cathode material. This process ensures the complete recycling of all the elements in mixed cathodes and the deep eutectic solvent can be reused. The regenerated LiFe0.5Mn0.5PO4 has an increased mean voltage (3.68 V versus Li/Li+) and energy density (559 Wh kg–1) compared with a commercial LiFePO4 (3.38 V and 524 Wh kg–1). The proposed upcycling strategy can expand at a gram-grade scale and was also applicable for LiFe0.5Mn0.5PO4 recovery, thus achieving a closed-loop recycling between the mixed spent cathodes and the next generation cathode materials. Techno-economic analysis shows that this strategy has potentially high environmental and economic benefits, while providing a sustainable approach for the value-added utilization of waste battery materials.

Abstract Two-dimensional materials with ultrahigh in-plane thermal conductivity are ideal for heat spreader applications but cause significant thermal contact resistance in complex interfaces, limiting their use as thermal interface materials. In this study, we present an interfacial phonon bridge strategy to reduce the thermal contact resistance of boron nitride nanosheets-based composites. By using a low-molecular-weight polymer, we are able to manipulate the alignment of boron nitride nanosheets through sequential stacking and cutting, ultimately achieving flexible thin films with a layer of arc-like structure superimposed on perpendicularly aligned ones. Our results suggest that arc-like structure can act as a phonon bridge to lower the contact resistance by 70% through reducing phonon back-reflection and enhancing phonon coupling efficiency at the boundary. The resulting composites exhibit ultralow thermal contact resistance of 0.059 in2 KW−1, demonstrating effective cooling of fast-charging batteries at a thickness 2-5 times thinner than commercial products.

Abstract Bifacial perovskite solar cells have shown great promise for increasing power output by capturing light from both sides. However, the suboptimal optical transmittance of back metal electrodes together with the complex fabrication process associated with front transparent conducting oxides have hindered the development of efficient bifacial PSCs. Here, we present a novel approach for bifacial perovskite devices using single-walled carbon nanotubes as both front and back electrodes. single-walled carbon nanotubes offer high transparency, conductivity, and stability, enabling bifacial PSCs with a bifaciality factor of over 98% and a power generation density of over 36%. We also fabricate flexible, all-carbon-electrode-based devices with a high power-per-weight value of 73.75 W g−1 and excellent mechanical durability. Furthermore, we show that our bifacial devices have a much lower material cost than conventional monofacial PSCs. Our work demonstrates the potential of SWCNT electrodes for efficient, stable, and low-cost bifacial perovskite photovoltaics.

Abstract Developing highly efficient catalysts is significant for Li-CO2 batteries. However, understanding the exact structure of catalysts during battery operation remains a challenge, which hampers knowledge-driven optimization. Here we use X-ray absorption spectroscopy to probe the reconstruction of CoSx (x = 8/9, 1.097, and 2) pre-catalysts and identify the local geometric ligand environment of cobalt during cycling in the Li-CO2 batteries. We find that different oxidized states after reconstruction are decisive to battery performance. Specifically, complete oxidation on CoS1.097 and Co9S8 leads to electrochemical performance deterioration, while oxidation on CoS2 terminates with Co-S4-O2 motifs, leading to improved activity. Density functional theory calculations show that partial oxidation contributes to charge redistributions on cobalt and thus facilitates the catalytic ability. Together, the spectroscopic and electrochemical results provide valuable insight into the structural evolution during cycling and the structure-activity relationship in the electrocatalyst study of Li-CO2 batteries.

Abstract Adding extra raw materials for direct recycling or upcycling is prospective for battery recycling, but overlooks subtracting specific components beforehand can facilitate the recycling to a self-sufficient mode of sustainable production. Here, a subtractive transformation strategy of degraded LiNi0.5Co0.2Mn0.3O2 and LiMn2O4 to a 5 V-class disordered spinel LiNi0.5Mn1.5O4-like cathode material is proposed. Equal amounts of Co and Ni from degraded materials are selectively extracted, and the remaining transition metals are directly converted into Ni0.4Co0.1Mn1.5(CO3)2 precursor for preparing cathode material with in-situ Co doping. The cathode material with improved conductivity and bond strength delivers high-rate (10 C and 20 C) and high-temperature (60 °C) cycling stability. This strategy with no extra precursor input can be generalized to practical degraded black mass and reduces the dependence of current cathode production on rare elements, showing the potential of upcycling from the spent to a next-generation 5 V-class cathode material for the sustainable Li-ion battery industry.

Abstract The practical applications of solar-driven water splitting pivot on significant advances that enable scalable production of robust photoactive films. Here, we propose a proof-of-concept for fabricating robust photoactive films by a particle-implanting technique (PiP) which embeds semiconductor photoabsorbers in the liquid metal. The strong semiconductor/metal interaction enables resulting films efficient collection of photogenerated charges and superior photoactivity. A photoanode of liquid-metal embraced BiVO4 can stably operate over 120 h and retain ~ 70% of activity when scaled from 1 to 64 cm2. Furthermore, a Z-scheme photocatalyst film of liquid-metal embraced BiVO4 and Rh-doped SrTiO3 particles can drive overall water splitting under visible light, delivering an activity 2.9 times higher than that of the control film with gold support and a 110 h stability. These results demonstrate the advantages of the PiP technique in constructing robust and efficient photoactive films for artificial photosynthesis.

Abstract Although zinc‒air batteries (ZABs) are regarded as one of the most prospective energy storage devices, their practical application has been restricted by poor air electrode performance. Herein, we developed a free‐standing air electrode that is fabricated on the basis of a multifunctional three‐dimensional interconnected graphene network. Specifically, a three‐dimensional interconnected graphene network with fast mass and electron transport ability, prepared by catalyzing growth of graphene foam on nickel foam and then filling reduced graphene oxide into the pores of graphene foam, is used to anchor iron phthalocyanine molecules with atomic Fe‒N4 sites for boosting the oxygen reduction during discharging and nanosized FeNi hydroxides for accelerating the oxygen evolution during charging. As a result, the obtained air electrode exhibited an ultra‐small electrocatalytic overpotential of 0.603 V for oxygen reactions, a high peak power density of 220.2 mW cm‒2, and a small and stable charge‒discharge voltage gap of 0.70 V at 10 mA cm‒2 after 1136 cycles. Furthermore, in situ Raman spectroscopy together with theoretical calculations confirmed that phase transformation of FeNi hydroxides takes place from α‐Ni(OH)x to β‐Ni(OH)x to γ‐Ni(3+δ)+OOH for the oxygen evolution reaction and Ni is the active center while Fe enhances the activity of Ni active sites.

Abstract Advancing fast‐charging technology is an important strategy for the development of alkali metal ion batteries (AMIBs). The exploitation of a new generation of anode material system with high‐rate performance, high capacity, and low risk of lithium/sodium/potassium plating is critical to realize fast‐charging capability of AMIBs while maintaining high energy density and safety. Among them, phosphorus‐based anodes including phosphorus anodes and metal phosphide anodes have attracted wide attention, due to their high theoretical capacities, safe reaction voltages, and natural abundance. In this review, we summarize the research progress of different phosphorus‐based anodes for fast‐charging AMIBs, including material properties, mechanisms for storing alkali metal ions, key challenges and solution strategies for achieving fast‐charging capability. Moreover, the future development directions of phosphorus‐based anodes in fast‐charging AMIBs are highlighted.

Abstract Recycling cathode materials from spent lithium‐ion batteries (LIBs) is critical to a sustainable society as it will relief valuable but scarce recourse crises and reduce environment burdens simultaneously. Different from conventional hydrometallurgical and pyrometallurgical recycling methods, direct regeneration relies on non‐destructive cathode‐to‐cathode mode, and therefore, more time and energy‐saving along with an increased economic return and reduced CO2 footprint. This review retrospects the history of direct regeneration and discusses state‐of‐the‐art development. The reported methods, including high‐temperature solid‐state, hydrothermal/ionothermal, molten salt thermochemistry, and electrochemical method, are comparatively introduced, targeting at illustrating their underlying regeneration mechanism and applicability. Further, representative repairing and upcycling studies on wide‐applied cathodes, including LiCoO2 (LCO), ternary oxides, LiFePO4 (LFP), and LiMn2O4 (LMO), are presented, with an emphasis on milestone cases. Despite these achievements, there remain several critical issues that shall be addressed before the commercialization of the mentioned direct regeneration methods.

Boron nitride nanosheet (BNNS)-based thermal management materials (TMMs) are increasingly vital in the rapidly evolving electronics industry but face limitations due to the anisotropic thermal conductivity of BNNS. Here, by ultrafast sintering, we synthesized cohesive BNNS microspheres (CBMs) with good processability and a strong ability to build isotropic thermally conductive pathways in various types of TMMs. This process produced the rapid fusion of BNNSs into spheres with a smooth surface, which weakens particle interactions and thus improves the ability to fill space including free-flowing properties (a low angle of repose of 21.6°) and dense packing behavior (a high tap density of 0.457 g cm-3). Additionally, such structure also allows for uniform distribution of stress under intense shearing, leading to a strong disintegration resistance which improves the processability and the quality of dispersal. By simple mixing, an isotropic thermal conductivity of 10.4 W m-1 K-1 was achieved with 65 wt% of CBM in the composite. Benefiting from its great processability and thermal conductivity enhancing ability, CBM was fabricated into various types of TMM such as pre-cured (pad), fluidic (grease), and in situ cured (adhesive, potting compound) products, all of which outperform industrial products. CBM represented a significant advancement in the development of high-performance TMMs, especially in high-efficiency fabrication and product diversity. [ABSTRACT FROM AUTHOR]

Non-layered two-dimensional (2D) materials have sparked much interest recently due to their atomic thickness, large surface area, thickness- and facet-dependent properties. Currently, these materials are mainly grown from wet-chemistry methods but suffer from small size, low quality, and multi-facets, which is a major challenge hindering their facet-dependent property studies and applications. Here, we report the facet-engineered growth (FEG) of non-layered 2D manganese chalcogenides (MnX, X = S, Se, Te) based on the chemical vapor deposition method. The as-grown samples exhibit large-area surfaces of single facet, high-crystallinity, and ordered domain orientation. As a proof-of-concept, we show the facet-dependent electrocatalytic property of non-layered 2D MnSe, proving they are ideal candidates for fundamental research. Furthermore, we elucidate the underlying mechanism of FEG during the vapor growth process by the interfacial energy derived nucleation models. The method developed in this work provides new opportunities for regulating and designing the structure of 2D materials. [ABSTRACT FROM AUTHOR]