Abstract
Graphene-based photodetectors have attracted significant attention for high-speed optical communication due to their large bandwidth, compact footprint, and compatibility with silicon-based ...photonics platform. Large-bandwidth silicon-based optical coherent receivers are crucial elements for large-capacity optical communication networks with advanced modulation formats. Here, we propose and experimentally demonstrate an integrated optical coherent receiver based on a 90-degree optical hybrid and graphene-on-plasmonic slot waveguide photodetectors, featuring a compact footprint and a large bandwidth far exceeding 67 GHz. Combined with the balanced detection, 90 Gbit/s binary phase-shift keying signal is received with a promoted signal-to-noise ratio. Moreover, receptions of 200 Gbit/s quadrature phase-shift keying and 240 Gbit/s 16 quadrature amplitude modulation signals on a single-polarization carrier are realized with a low additional power consumption below 14 fJ/bit. This graphene-based optical coherent receiver will promise potential applications in 400-Gigabit Ethernet and 800-Gigabit Ethernet technology, paving another route for future high-speed coherent optical communication networks.
High‐capacity cathodes and anodes in energy storage area are required for delivering high energy density due to the ever‐increasing demands in the applications of electric vehicles and power grids, ...which suffer from significant safety concerns and poor cycling stability at the current stage. All‐solid‐state lithium batteries (ASSLBs) have been considered to be particularly promising within the new generation of energy storage, owing to the superiority of safety, wide potential window, and long cycling life. As the key component in ASSLBs, individual solid electrolytes that can meet practical application standards are very rare due to poor performance. To the present day, numerous research efforts have been expended to find applicable solid‐state electrolytes and tremendous progress has been achieved, especially for garnet‐type solid electrolytes. Nevertheless, the garnet‐type solid electrolyte is still facing some crucial dilemmas. Hence, the issues of garnet electrolytes' ionic conductivity, the interfaces between electrodes and garnet solid electrolytes, and application of theoretical calculation on garnet electrolytes are focuses in this review. Furthermore, prospective developments and alternative approaches to the issues are presented, with an aim to improve understanding of garnet electrolytes and promote their practical applications in solid‐state batteries.
Garnet solid electrolytes are promising on account of improved safety and higher energy density, which can take advantage of anodic Li. In this review, three key issues related to garnet electrolytes are presented in detail, including ionic conductivity, garnet electrolyte/metal Li interfaces, and theoretical calculations applied to garnet electrolytes.
Abstract
Terahertz isolators, one of the typical nonreciprocal devices that can break Lorentz reciprocity, are indispensable building blocks in terahertz systems for their critical functionality of ...manipulating the terahertz flow. Here, we report an integrated terahertz isolator based on the magneto-optical effect of a nonreciprocal resonator. By optimizing the magneto-optical property and the loss of the resonator, we experimentally observe unidirectional propagation with an ultrahigh isolation ratio reaching up to 52 dB and an insertion loss around 7.5 dB at ~0.47 THz. With a thermal tuning method and periodic resonances, the isolator can operate at different central frequencies in the range of 0.405–0.495 THz. This on-chip terahertz isolator will not only inspire more solutions for integrated terahertz nonreciprocal devices, but also have the feasibility for practical applications such as terahertz sensing and reducing unnecessary reflections in terahertz systems.
A hexapod PtRuCu nanocrystalline alloy material is successfully fabricated by a facile approach based on Stranski–Krastanov growth and galvanic replacement and used as an efficient catalyst for ...direct methanol fuel cells (DFMCs). Because of the synergetic effect of metallic elements in the methanol oxidation, the activity and durability of the prepared PtRuCu/C catalyst is significantly enhanced. It has a mass activity of 1.35 A mgPt –1 and a specific activity of 3.92 mA cm–2, which are 3.8 and 8.2 times higher than those of Pt/C, respectively. Its mass activity only decreases 27% after 800 CV cycles compared with Pt/C (60% decline), indicating the admirable stability of the PtRuCu catalyst.
As a promising cathode material for high performance lithium ion batteries, olivine LiMnxFe1−xPO4 (LMFP) combines the high safety of LiFePO4 and the high energy density of LiMnPO4. However, there are ...still obstacles to overcome for achieving higher rate performance, especially its inherent low electronic conductivity and Li+ diffusion coefficient. Here, the restricting factors for realizing high rate performance LMFP cathode materials are reviewed systematically. The bulk properties that affect the internal ion transport and electronic conduction are thoroughly expounded, particularly the phase transition mechanism, lattice distortion, point defects, element doping, Fe/Mn ratio and particle morphology. Moreover, the effect of utilizing a carbon-based/non-carbon material coating for improving the interface structure on rate performance is discussed comprehensively. A particular emphasis is placed on the design of LMFP-based batteries with high rate capability as well from the aspect of cell preparation technology, including the electrolyte selection and electrode design. Finally, on the basis of state-of-the-art understanding of bulk properties, the interface structure and cell preparation engineering, several technical challenges and research trends in improving the rate performance of LMFP cathode materials are proposed.
Highlights
Interfacial bonding strategy has been successfully applied to address the high overpotential issue of sacrificial additives, which reduced the decompositon potential of Na
2
C
2
O
4
from ...4.50 to 3.95 V.
Ultra-low-dose technique assisted commercial sodium ion capacitor (AC//HC) could deliver a remarkable energy density of 118.2 Wh kg
−1
as well as excellent cycle stability.
In-depth decomposition mechanism of sacrificial compound and the relative influence after pre-metallation were revealed by advanced in situ and ex situ characterization approaches.
Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode, thereby elevating the cycle performance as well as open-circuit voltage for full metal ion capacitors (MICs). However, suffered from massive-dosage abuse, exorbitant decomposition potential, and side effects of decomposition residue, the wide application of sacrificial approach was restricted. Herein, assisted with density functional theory calculations, strongly coupled interface (M–O–C, M = Li/Na/K) and electron donating group have been put forward to regulate the band gap and highest occupied molecular orbital level of metal oxalate (M
2
C
2
O
4
), reducing polarization phenomenon and Gibbs free energy required for decomposition, which eventually decrease the practical decomposition potential from 4.50 to 3.95 V. Remarkably, full sodium ion capacitors constituted of commercial materials (activated carbon//hard carbon) could deliver a prominent energy density of 118.2 Wh kg
−1
as well as excellent cycle stability under an ultra-low dosage pre-sodiation reagent of 15–30 wt% (far less than currently 100 wt%). Noteworthily, decomposition mechanism of sacrificial compound and the relative influence on the system of MICs after pre-metallation were initially revealed by in situ differential electrochemical mass spectrometry, offering in-depth insights for comprehending the function of cathode additives. In addition, this breakthrough has been successfully utilized in high performance lithium/potassium ion capacitors with Li
2
C
2
O
4
/K
2
C
2
O
4
as pre-metallation reagent, which will convincingly promote the commercialization of MICs.
With the rapid development of Industry 4.0, the importance of cyber security for industrial control systems has become increasingly prominent. The complexity and diversity of industrial control ...systems result in data with high dimensionality and strong correlation, posing significant challenges in obtaining labeled data. However, current intrusion detection methods often demand large amounts of labeled data for effective training. To address this limitation, this paper proposes a semi-supervised anomaly detection framework, called SFSD, which leverages feature selection and deviation networks to detect anomalies in industrial control systems. Specifically, we introduce a feature selection algorithm (IG-PCA) that utilizes information gain and principal component analysis to reduce the dimensionality of features in industrial control data by eliminating redundant features. Then, we propose a semi-supervised learning method based on an improved deviation network, which utilizes an anomaly scoring network to learn end-to-end anomaly scores for the training data, thus assigning anomaly scores to each training data. Finally, using a limited amount of anomaly-labeled data, we design a specific deviation loss function to optimize the anomaly scoring network, enabling a significant score bias between positive and negative samples. Experimental results demonstrate that the proposed SFSD outperforms existing semi-supervised anomaly detection frameworks by improving the accuracy and detection rate by an average of 1–2%. Moreover, SFSD requires less training time compared to existing frameworks, resulting in a training time reduction of approximately 10% or more.
Developing drugs increasingly relies on mechanistic modeling and simulation. Models that capture causal relations among genetic drivers of oncogenesis, functional plasticity, and host immunity ...complement wet experiments. Unfortunately, formulating such mechanistic cell-level models currently relies on hand curation, which can bias how data is interpreted or the priority of drug targets. In modeling molecular-level networks, rules and algorithms are employed to limit a priori biases in formulating mechanistic models. Here we combine digital cytometry with Bayesian network inference to generate causal models of cell-level networks linking an increase in gene expression associated with oncogenesis with alterations in stromal and immune cell subsets from bulk transcriptomic datasets. We predict how increased Cell Communication Network factor 4, a secreted matricellular protein, alters the tumor microenvironment using data from patients diagnosed with breast cancer and melanoma. Predictions are then tested using two immunocompetent mouse models for melanoma, which provide consistent experimental results.
The rapid growth in global electric vehicles (EVs) sales has promoted the development of Co-free, Ni-rich layered cathodes for state-of-the-art high energy-density, inexpensive lithium-ion batteries ...(LIBs). However, progress in their commercial use has been seriously hampered by exasperating performance deterioration and safety concerns. Herein, a robust single-crystalline, Co-free, Ni-rich LiNi0.95Mn0.05O2 (SC-NM95) cathode is successfully designed using a molten salt-assisted method, and it exhibits better structural stability and cycling durability than those of polycrystalline LiNi0.95Mn0.05O2 (PC-NM95). Notably, the SC-NM95 cathode achieves a high discharge capacity of 218.2 mAh g−1, together with a high energy density of 837.3 Wh kg−1 at 0.1 C, mainly due to abundant Ni2+/Ni3+ redox. It also presents an outstanding capacity retention (84.4%) after 200 cycles at 1 C, because its integrated single-crystalline structure effectively inhibits particle microcracking and surface phase transformation. In contrast, the PC-NM95 cathode suffers from rapid capacity fading owing to the nucleation and propagation of intergranular microcracking during cycling, facilitating aggravated parasitic reactions and rock-salt phase accumulation. This work provides a fundamental strategy for designing high-performance single-crystalline, Co-free, Ni-rich cathode materials and also represents an important breakthrough in developing high-safe, low-cost, and high-energy LIBs.
Robust single-crystalline Co-free Ni-rich LiNi0.95Mn0.05O2 (SC-NM95) cathode successfully designed by molten salt-assisted method exhibits the enhanced structural stability and cycling durability compared with that of polycrystalline LiNi0.95Mn0.05O2 (PC-NM95) cathode. Display omitted
•Single-crystalline Co-free Ni-rich LiNi0.95Co0.05O2 cathode was firstly designed and systematically explored.•The SC-NM95 cathode presents outstanding structural stability and cycling durability.•The performance degradations of PC-NM95 were attributed to the microcracking formation and structural transformations.•It provides insights into the fundamental design of high-performance single-crystalline Co-free Ni-rich cathodes.
Sodium-ion batteries (SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The ...irreversible Na+ ions consumption during the first cycle of charge/discharge process (due to the formation of the solid electrolyte interface (SEI) on the electrode surface and other irreversible reactions) is the factor that determines high performance SIBs and largely reduces the capacity of the full cell SIBs. Thus, the initial coulombic efficiency (ICE) of SIBs for both anode and cathode materials, is a key parameter for high performance SIBs, and the point is to increase the transport rate of the Na+ ions. Therefore, developing SIBs with high ICE and rate performance becomes vital to boost the commercialization of SIBs. Here we provide a review on the methods to improve the ICE and the rate performance, by summarizing some methods of improving the ICE and rate performance of the anode and cathode materials for SIBs, and end by a conclusion with some perspectives and recommendations.
Display omitted
To improve the initial coulombic efficiency (ICE) and the rate performance of the sodium-ion batteries (SIBs), some methods are discussed in the present work, following recent advancements, regarding the electrode materials (anode and cathode). The methods such as material structure modification, surface engineering, heteroatom doping, material alloying, co-precipitation, have been found to be effective to solve the problem of low ICE and rate performance of the SIBs
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