Cubic silicon carbide (3C-SiC) has superior mobility and thermal conduction than that of widely applied hexagonal 4H-SiC. Moreover, much lower concentration of interfacial traps between insulating oxide gate and 3C-SiC helps fabricate reliable and long-life devices like metal-oxide-semiconductor field effect transistors (MOSFETs). However, the growth of high quality and wafer-scale 3C-SiC crystals has remained a big challenge up to now despite of decades-long efforts by researchers because of its easy transformation into other polytypes during growth, limiting the development of 3C-SiC based devices. Herein, we report that 3C-SiC can be made thermodynamically favored from nucleation to growth on a 4H-SiC substrate by top-seeded solution growth technique (TSSG), beyond what’s expected by classic nucleation theory. This enables the steady growth of high-quality and large-size 3C-SiC crystals (2~4-inch in diameter and 4.0~10.0 mm in thickness) sustainable. The as-grown 3C-SiC crystals are free of other polytypes and have high crystalline quality. Our findings broaden the mechanism of hetero-seed crystal growth and provide a feasible route to mass production of 3C-SiC crystals, offering new opportunities to develop power electronic devices potentially with better performances than those based on 4H-SiC.
SnO2, with its high theoretical capacity, abundant resources, and environmental friendliness, is widely regarded as a potential anode material for lithium-ion batteries (LIBs). Nevertheless, the coarsening of the Sn nanoparticles impedes the reconversion back to SnO2, resulting in low coulombic efficiency and rapid capacity decay. In this study, we fabricated a heterostructure by combining SnO2 nanoparticles with MoS2 nanosheets via plasma-assisted milling. The heterostructure consists of in-situ exfoliated MoS2 nanosheets predominantly in 1T phase, which tightly encase the SnO2 nanoparticles through strong bonding. This configuration effectively mitigates the volume change and particle aggregation upon cycling. Moreover, the strong affinity of Mo, which is the lithiation product of MoS2, toward Sn plays a pivotal role in inhibiting the coarsening of Sn nanograins, thus enhancing the reversibility of Sn to SnO2 upon cycling. Consequently, the SnO2/MoS2 heterostructure exhibits superb performance as an anode material for LIBs, demonstrating high capacity, rapid rate capability, and extended lifespan. Specifically, discharged/charged at a rate of 0.2 A g-1 for 300 cycles, it achieves a remarkable reversible capacity of 1173.4 mAh g-1. Even cycled at high rates of 1.0 and 5.0 A g-1 for 800 cycles, it still retains high reversible capacities of 1005.3 and 768.8 mAh g-1, respectively. Moreover, the heterostructure exhibits outstanding electrochemical performance in both full LIBs and sodium-ion batteries.
The emergence of polymerized small molecule acceptors (PSMAs) has significantly improved the performance of all-polymer solar cells (all-PSCs). However, the pace of device engineering lacks behind that of materials development, so that a majority of the PSMAs have not fulfilled their potentials. Furthermore, most high-performance all-PSCs rely on the use of chloroform as the processing solvent. For instance, the recent high-performance PSMA named PJ1-γ, with high LUMO and HOMO levels, could only achieve a PCE of 16.1% with a high-energy-level donor (JD40) using chloroform. Herein, we present a methodology combining sequential processing (SqP) with the addition of 0.5%wt PC71BM as a solid additive (SA) to achieve an impressive efficiency of 18.0% for all-PSCs processed from toluene, an aromatic hydrocarbon solvent. Compared to the conventional blend-casting (BC) method whose best efficiency (16.7%) could only be achieved using chloroform, the SqP method significantly boosted the device efficiency using toluene as the processing solvent. In addition, the donor we employ is the classic PM6 that has deeper energy levels than JD40, which provides low energy loss for the device. We compare the results with another PSMA (PYF-T-o) with the same method. Finally, an improved photostability of the SqP devices with the incorporation of SA is demonstrated.
Manufacturing thin-film components is crucial for achieving high-efficiency and high-power thermal batteries (TBs). However, developing binders with low gas production at the operating temperature range of TBs (400−550 °C) has proven to be a significant challenge. Here we report the use of acrylic acid derivative terpolymer (LA136D) as a low-volatile binder for thin-film cathode fabrication and studied the chain scission and chemical bond-breaking mechanisms in pyrolysis. It is shown LA136D defers to random-chain scission and cross-linking chain scission mechanisms, which gifts it with a low proportion of volatile products (ψ, ψ=39.2wt%) at even up to 550 °C, well below those of the conventional PVDF (77.6wt%) and SBR (99.2wt%) binders. Surprisingly, LA136D contributes to constructing a thermal shock-resistant cathode due to the step-by-step bond-breaking process. This is beneficial for the overall performance of TBs. In a 130 s pulse discharging test, the thin-film cathodes exhibited a remarkable 440% reduction in polarization and 300% enhancement in the utilization efficiency of cathode materials, while with just a slight increase of 0.05 MPa in gas pressure compared with traditional “thick-film” cathode. Our work highlights the potential of LA136D as a low-volatile binder for thin-film cathodes and shows the feasibility of manufacturing high-efficiency and high-power TBs through polymer molecule engineering.
Solar steam generation is a promising water purification technology due to its low-cost and environmentally friendly applications in water purification and desalination. However, hydrophilic or hydrophobic materials alone are insufficient in achieving necessary characteristics for constructing high-quality solar steam generators with good comprehensive properties. Herein, novel hydrophile/hydrophobe amphipathic Janus nanofibers aerogel is designed and used as a host material for preparing solar steam generators. The product consists of an internal cubic aerogel and an external layer of photothermal materials. The internal aerogel is composed of electrospun amphipathic Janus nanofibers. Owing to the unique composition and structure, the prepared solar steam generator integrates the features of high water evaporation rate (2.944 kg·m-2·h-1 under 1 kW m-2 irradiation), self-floating, salt-resisting, and fast performance recovery after flipping. Moreover, the product also exhibits excellent properties on desalination and removal of organic pollutants. Compared with traditional hydrophilic aerogel host material, the amphipathic Janus nanofibers aerogel brings much higher water evaporation rate and salt resistance.
To unlock the full potential of PSCs, machine learning (ML) was implemented in this research to predict the best combination of mesoporous-titanium dioxide (mp-TiO2) and weight percentage (wt%) of phenyl-C61-butyric acid methyl ester (PCBM), along with the current density (Jsc), open-circuit voltage (Voc), fill factor (ff) and energy conversion efficiency (ECE). Then, the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM-PSCs with nanopatterned TiO2 layer. Subsequently, the PCBM-PSCs with nanopatterned TiO2 layers were fabricated and characterized to further understand the dual effects of nanopatterning depth and wt% of PCBM on PSCs. Experimentally, the highest ECE of 17.336% is achieved at 127 nm nanopatterning depth and 0.10 wt% of PCBM, where the Jsc, Voc and ff are 22.877 mA/cm2, 0.963 V and 0.787, respectively. The measured Jsc, Voc, ff and ECE values show consistencies with the ML prediction. Hence, these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs, but also highlighted that nanopatterning depth has a significant impact on Jsc, and the incorporation of PCBM on perovskite layer influenced the Voc and ff, which further boosted the performance of PSCs.
Due to poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is water-processable, thermally stable and highly conductive, PEDOT:PSS and its composites have been considered to be one of the most promising flexible thermoelectric materials. However, the PEDOT:PSS film prepared from its commercial aqueous dispersion usually has quite low conductivity, thus cannot be directly utilized for thermoelectric applications. Here, a simple environmentally friendly strategy via femtosecond laser irradiation without any chemical dopants and treatments was demonstrated. Under optimal conditions, the electrical conductivity of the treated film is increased to 803.1 S/cm from 1.2 S/cm around three order of magnitude higher, and the power factor is improved to 19.0 μW·m-1·K-2, which is enhanced more than 200 times. The mechanism for such remarkable enhancement was attributed to the transition of the PEDOT chains from a coil to a linear or expanded coil conformation, reduction of the interplanar stacking distance, and the removal of insulating PSS with increasing the oxidation level of PEDOT, facilitating the charge transportation. This work presents an effective route for fabricating high-performance flexible conductive polymer films and wearable thermoelectric devices.
In this work, a modified polyurethane adhesive (PUA) was prepared to realize a convenient encapsulation strategy for lead efficient sedimentation and for attachable perovskite solar cells (PSCs). The modified PUA can completely self-healing within 45 minutes at room temperature and it has a lead ion blocking rate of 99.3% in the dripping experiment. The PUA film can directly contact with the metal electrode surface with a slight efficiency improvement from 23.96% to 24.15%. The thermal stability of 65℃ and humidity stability of 55% RH is superior to the encapsulated devices with polyisobutylene. The PUA film has strong adhesion to flexible substrate, and the initial efficiency of flexible perovskite module (17.2%) encapsulated by PUA remains 92.6% within 1825 h. These results suggest PUA encapsulation route is universal for rigid and flexible PSCs with enhanced stability and low lead hazardous. Moreover, it was found that the flexible PSCs can be well attached to varied substrates with PUA, providing a facile route for the attachable PSCs in various scenarios without additional encapsulation and installation.
With the rapid development of science and technology, paper-based functional materials have become the core of the field of new materials. Recently, they have received extensive attention in the field of energy storage due to their advantages of rich and adjustable porous network structure, good flexibility. As an important energy storage device, paper-based supercapacitors have important application prospects in many fields, and have also received extensive attention from researchers in recent years. At present, researchers have modified and regulated paper-based materials by different means such as structural design and material composition to enhance their electrochemical storage capacity. The development of paper-based supercapacitors provides an important direction for the development of green and sustainable energy. Therefore, it is of great significance to summarize the relevant work of paper-based supercapacitors for their rapid development and application. In this review, the recent research progress of paper-based supercapacitors based on cellulose was summarized in terms of various cellulose-based composites, preparation skills and electrochemical performance. Finally, some opinions on the problems in the development of this field and the future development trend were proposed. It is hoped that this review can provide valuable references and ideas for the rapid development of paper-based energy storage devices.
Anode-free Li-metal batteries (AFLBs) are of significant interest to energy storage industries due to their intrinsically high energy. However, the accumulative Li dendrites and dead Li continuously consume active Li during cycling. That results in a short lifetime and low Coulombic efficiency (CE) of AFLBs. Introducing effective electrolyte additives can improve the Li deposition homogeneity and solid-state interphase (SEI) stability for AFLBs. Herein, we reveal that introducing dual additives, composed of LiAsF6 and FEC, into a commercial carbonate electrolyte will boost the cycle life and average CE of NCM||Cu AFLBs. The NCM||Cu AFLBs with the dual additives exhibit a capacity retention of about 75% after 50 cycles, much higher than those with bare electrolytes (35%). The average CE of the NCM||Cu AFLBs with additives can maintain 98.3% over 100 cycles. In contrast, the average CE without additives rapidly decline to 97% after only 50 cycles. In situ Raman measurements reveal that the prepared dual additives facilitate denser and smoother Li morphology during Li deposition. The dual additives significantly suppress the Li dendrite growth, enabling stable SEI formation on anode and cathode surfaces. Our results provide a broad view of developing low-cost and high-effective functional electrolytes for high-energy and long-life AFLBs.
A suitable interface between the electrode and electrolyte is crucial in achieving highly stable electrochemical performance for Li-ion batteries, as facile ionic transport is required. Recently, intriguing research and development have been carried out to form a stable interface between the electrode and electrolyte. Therefore, it is essential to investigate emerging knowledge and contextualize it. The nanoengineering of the electrode-electrolyte interface has been actively researched both at the electrode/electrolyte and interphase levels, which calls for significant attention. This review presents and summarizes some recent advances aimed at nanoengineering approaches to build a more stable electrode-electrolyte interface and assess the impact of each approach adopted. Furthermore, future perspectives on the feasibility and practicality of each approach will also be reviewed in detail. Finally, this review aids in projecting a more sustainable research pathway for a nanoengineered interphase design between electrode and electrolyte, which is pivotal for high-performance, thermally stable Li-ion batteries.
The interfacial contacts between the electron transporting layers (ETLs) and the photoactive layers are crucial to device performance and stability for OSCs with inverted architecture. Herein, atomic layer deposition (ALD) fabricated ultrathin Al2O3 layers are applied to modify the ETLs/active blends (PM6:BTP-BO-4F) interfaces of OSCs, thus improving device performance. The ALD-Al2O3 thin layers on ZnO significantly improved its surface morphology, which led to the decreased work function of ZnO and reduced recombination losses in devices. The simultaneous increase in open-circuit voltage (), short-circuit current density () and fill factor (FF) were achieved for the OSCs incorporated with ALD-Al2O3 interlayers of a certain thickness, which produced a maximum PCE of 16.61%. Moreover, the ALD-Al2O3 interlayers had significantly enhanced device stability by suppressing degradation of the photoactive layers induced by the photocatalytic activity of ZnO and passivating surface defects of ZnO that may play the role of active sites for the adsorption of oxygen and moisture.
Solar vapour generation (SVG) represents a promising technique for seawater desalination to alleviate the global water crisis and energy shortage. One of its main bottleneck problems is that the evaporation efficiency and stability are limited by salt crystallization under high-salinity brines. Herein, we demonstrate that the 3D porous melamine-foam (MF) wrapped by a type of self-assembling composite materials based on reduced polyoxometalates (i.e. heteropoly blue, HPB), oleic acid (OA) and polypyrrole (PPy) (labeled with MF@HPB-PPyn-OA) can serve as efficient and stable SVG material at high-salinity. Structural characterizations of MF@HPB-PPyn-OA indicate that both hydrophilic region of HPBs and hydrophobic region of OA co-exist on the surface of composite materials, optimizing the hydrophilic and hydrophobic interfaces of the SVG materials, and fully exerting its functionality for ultrahigh water-evaporation and anti-salt fouling. The optimal MF@HPB-PPy10-OA operates continuously and stably for over 100 h in 10 wt% brine. Furthermore, MF@HPB-PPy10-OA accomplishes complete salt-water separation of 10 wt% brine with 3.3 kg m-2 h-1 under 1-sun irradiation, yielding salt harvesting efficiency of 96.5%, which belongs to the record-high of high-salinity systems reported so far and reaches zero liquid discharge. Moreover, the low-cost of MF@HPB-PPy10-OA (2.56 $/m2) suggests its potential application in the practical SVG technique.
It is well accepted that a lithiophilic interface can effectively regulate Li deposition behaviors, but the influence of the lithiophilic interface is gradually diminished upon continuous Li deposition that completely isolates Li from the lithiophilic metals. Herein, we perform in-depth studies on the creation of dynamic alloy interface upon Li deposition, arising from the exceptionally high diffusion coefficient of Hg in the amalgam solid solution. As a comparison, other metals such as Au, Ag and Zn have typical diffusion coefficients of 10-20 orders of magnitude lower than for Hg in the similar solid solution phases. This difference induced compact Li deposition pattern with an amalgam substrate even with a high areal capacity of 55 mAh cm-2. This finding provides new insight into the rational design of Li anode substrate for the stable cycling of Li metal batteries.
The ever-increasing complexity of environmental pollutants urgently warrants the development of new detection technologies. In this context, sensors based on the optical properties of hydrogels enabling fast and easy in situ detection are attracting increasing attention. Herein, the target recognition and sensing mechanisms of two main types of optical hydrogels (OHs) are reviewed and discussed: photonic crystal hydrogels (PCHs) and fluorescent hydrogels (FHs). For PCHs, the environmental stimulus response, target receptors, inverse opal structures, and molecular imprinting techniques related to PCHs are reviewed and summarized. Furthermore, the different types of fluorophores (i.e., compound probes, biomacromolecules, quantum dots, and luminescent microbes) of FHs are summarized. Finally, the data from 138 papers about different OHs are extracted for secondary statistical analysis. The detection performance and potential of various OH types in different environmental pollutant detection scenarios are evaluated, and compared them to those obtained using the standard detection method. Based on this analysis, some possible development directions are proposed, including the fusion of various OHs, introduction of more hydrogel technologies from the biomedical field to the environmental pollutant detection field, and development of multifunctional sensor arrays.