Aqueous zinc-ion batteries (AZIBs) are emerging as a promising option for next-generation energy storage due to their abundant resources, affordability, eco-friendliness, and high safety levels. Manganese-based cathode materials, in particular, have garnered significant attention because of their high theoretical capacity and cost-effectiveness. However, they still face substantial challenges related to rate performance and cycling stability. To address these issues, researchers have developed various strategies. This review focuses on the key advancements in manganese-based cathode materials for AZIBs in recent years. It begins with a detailed analysis of the energy storage mechanisms in manganese-based cathodes. Next, it introduces a variety of manganese-based oxides, highlighting their distinct crystal structures and morphologies. It also outlines optimization strategies, such as ion doping (both monovalent ions and multivalent ions), the preparation of Mn-based metal-organic frameworks (MOFs), carbon materials coatings, and electrolyte optimization. These strategies have significantly improved the electrochemical performance of manganese-based oxide cathodes. By systematically analyzing these advancements, it aims to provide guidance for the development of high-performance manganese-based cathodes. Finally, it discusses prospective research directions for manganese-based cathodes in AZIBs.
Enzymatic biofuel cells (EBFCs), which generate electricity through electrochemical reactions between metabolites and O2/air, are considered a promising alternative power source for wearable and implantable bioelectronics. However, the main challenges facing EBFCs are the poor stability of enzymes and the low electron transfer efficiency between enzymes and electrodes. To enhance the efficiency of EBFCs, researchers have been focusing on the development of novel functional nanomaterials. This mini-review first introduces the working principles and types of EBFCs, highlighting the key roles of nanomaterials, such as enzyme immobilization and stabilization, promotion of electron transfer and catalytic activity. It then summarizes the recent advancements in their application in wearable and implantable devices. Finally, it explores future research direction and the potential of high-performance EBFCs for practical applications.
Developing environmentalyl friendly and energy-efficient CO2 adsorbents for post-combustion capture is a critical step toward achieving toward carbon neutrality. While aqueous amines and metal oxides have play pivotal roles in CO2 capture, their application is limited by issues such as secondary pollution and high energy consumption. In contrast, Zn-based metal-organic frameworks (Zn-based MOFs) have emerged as a green alternative, offering low toxicity reduced regeneration temperatures, and high efficiency in both CO2 adsorption and catalytic conversion into valuable fuels and chemicals. This mini review begins with a general introduction to MOFs in CO2 capture and conversion, followed by an overview of early studies on Zn-based MOFs for CO2 capture. It then summarizes recent research advancements in Zn-based MOFs for integrated CO2 capture and conversion. Finally, it discusses key challenges and future research directions for post-combustion CO2 capture and conversion using Zn-based MOFs.
Photoelectrochemical (PEC) water splitting, particularly self-biased PEC systems, holds great promise for solar energy utilization. However, the limited transparency of most photoelectrodes presents challenges in fabricating tandem photoelectrodes with photovoltaic (PV) cells for self-biased water splitting. Herein, a novel self-biased hybrid system integrating photoelectrodes (TiO2, BiVO4), beam splitters (BSs), and PV cell was proposed to enhance solar energy utilization and PEC water splitting performance. The results indicate that the integration of BSs significantly improves the current densities of both self-biased PV-PEC systems and single PEC systems. The current density of self-biased water splitting system with BSs exceeds that of the conventional TiO2 + BVO-PV system, and the intersection point of the I–V curves for the photoanodes and solar cell is closer to the maximum power output of the solar cell. The effective utilization of the solar spectrum by both the photoelectrode and the PV cell in the hybrid system with BSs significantly increases the power output by a factor of 18.8 compared to the conventional tandem self-biased system. The predicted results indicate that the hydrogen production rate of the system with BSs is 12.1 µmol/(h∙cm2), while the STH efficiency is enhanced by a factor of 12.38 and 19.87 compared to conventional TiO2 + BVO-PV and TiO2/BVO-PV tandem PV-PEC systems, respectively, demonstrating the advantage of the water splitting system with spectral BSs. In conclusion, this work provides an innovative approach of achieving self-biased water splitting by coupling spectral BSs with a PV-PEC system, resulting in improved solar energy harvesting efficiency.
The frame of membrane electrode assembly (MEA) influences the durability of proton exchange membrane fuel cell (PEMFC). In this paper, the thermal shock bench was applied as an accelerated aging test to explore the effect of frame sealing structure on MEA durability at different temperatures. Analysis of scanning electron microscope (SEM) images reveals that thermal shock results in the formation of cracks on the exposed proton exchange membrane (PEM) at the gap between the frame and the active area. Moreover, it breaks the bonding interface between the frame and the membrane and leads to the debonding of the adhesive, which exacerbates the risk of crossover of the reactant gas. A comparison of the single-layer and improved double-layer frame structures reveal that the mechanical damage is caused by frequent membrane wrinkles in the gap under temperature shock. However, addition of a cushion layer improves the continuity between the frame and the active area, and reduces deformation of the membrane, thereby preventing membrane damage.
This study explores the structural, electronic, and optical properties of tin-based halide perovskites, MSnX3 (M = Li, Na; X = Cl, Br, I), under varying pressure conditions. Using volume optimization and the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) method, it analyzes these perovskites in their cubic
An accurate assessment of the state of health (SOH) is the cornerstone for guaranteeing the long-term stable operation of electrical equipment. However, the noise the data carries during cyclic aging poses a severe challenge to the accuracy of SOH estimation and the generalization ability of the model. To this end, this paper proposed a novel SOH estimation model for lithium-ion batteries that incorporates advanced signal-processing techniques and optimized machine-learning strategies. The model employs a whale optimization algorithm (WOA) to seek the optimal parameter combination (K, α) for the variational modal decomposition (VMD) method to ensure that the signals are accurately decomposed into different modes representing the SOH of batteries. Then, the excellent local feature extraction capability of the convolutional neural network (CNN) was utilized to obtain the critical features of each modal of SOH. Finally, the support vector machine (SVM) was selected as the final SOH estimation regressor based on its generalization ability and efficient performance on small sample datasets. The method proposed was validated on a two-class publicly available aging dataset of lithium-ion batteries containing different temperatures, discharge rates, and discharge depths. The results show that the WOA-VMD-based data processing technique effectively solves the interference problem of cyclic aging data noise on SOH estimation. The CNN-SVM optimized machine learning method significantly improves the accuracy of SOH estimation. Compared with traditional techniques, the fused algorithm achieves significant results in solving the interference of data noise, improving the accuracy of SOH estimation, and enhancing the generalization ability.
The solid oxide fuel cell (SOFC) power system fueled by NH3 is considered one of the most promising solutions for achieving ship decarbonization and carbon neutrality. This paper addresses the technical challenges faced by NH3 fuel SOFC ship power system, including slow hydrogen (H2) production, low efficiency, and limited space. It introduces an innovative a NH3-integrated reactor for rapid H2 production, establishes a safe and efficient all-electric SOFC all-electric propulsion system adaptable to various sailing conditions. The system is validated using a 2 kW prototype experimental rig. Results show that the SOFC system, designed for a target ship, has a rated power of 96 kW and an electrical efficiency of 60.13%, meeting the requirements for rated cruising conditions. Under identical catalytic scenarios, the designed reactor, with highly efficient heat transfer, measuring 1.1 m in length, can achieve complete NH3 decomposition within 2.94 s, representing a 35% reduction in cracking time and a 42% decrease in required cabin space. During high-load voyage conditions, adjusting the circulation ratio (CR) and ammonia-oxygen ratio (A/O) improves system efficiency across a wide operational range. Among these adjustments, altering the A/O ratio proves to be the most efficient strategy. Under this configuration, the system achieves an efficiency of 55.02% at low load and 61.73% at high load, allowing operation across a power range of 20% to 110%. Experimental results indicate that the error for NH3 cracking H2 is less than 3% within the range of 570–700 °C, which is relevant to typical ship operation scenarios. At 656 °C, the NH3 cracking H2 rate reaches 100%. Under these conditions, the SOFC produces 2.045 kW of power with an efficiency of approximately 58.66%. The noise level detected is 58.6 dB, while the concentrations of CO2, NO, and SO2 in the flue gas approach zero. These findings support the transition of the shipping industry to green, clean systems, contributing significantly to future reductions in ocean carbon emissions.
Aqueous zinc metal batteries (ZMBs) are regarded as strong contenders in secondary battery systems due to their high safety and abundant resources. However, the cycling performance of the Zn anode and the overall performance of the cells have often been hindered by the formation of Zn dendrites and the occurrence of parasitic side reactions. In this paper, a surface electron reconfiguration strategy is proposed to optimize the adsorption energy and migration energy of Zn2+ for a better Zn2+ deposition/stripping process by adjusting the electronic structure of ceric dioxide (CeO2) artificial interface layer with copper atoms (Cu) doped. Both experimental results and theoretical calculations demonstrate that the Cu2Ce7Ox interface facilitates rapid transport of Zn2+ due to the optimized electronic structure and appropriate electron density, leading to a highly reversible and stable Zn anode. Consequently, the Cu2Ce7Ox@Zn symmetric cell exhibits an overpotential of only 24 mV after stably cycling for over 1600 h at a current density of 1 mA/cm2 and a capacity of 1 mAh/cm2. Additionally, the cycle life of Cu/Zn asymmetric cells exceeds 2500 h, with an average Coulombic efficiency of 99.9%. This paper provides a novel approach to the artificial interface layer strategy, offering new insights for improving the performance of ZMBs.
The curved bending regions of serpentine flow channels play a crucial role in mass transfer and the overall performance of the flow field in proton exchange membrane fuel cells (PEMFCs). This paper proposes a “2D Topology-Curvature Optimization” progressive design method to optimize the bend area structures, aiming to enhance PEMFC performance. Through numerical simulations, it compares the topology-curvature optimization model with both the algorithm-based optimization model and a validation model, and analyzes the mass transfer, heat transfer characteristics, and output performance of PEMFC under different flow fields. The results indicate that the optimized structures improve convection and diffusion within the flow field, effectively enhancing the transport and distribution of oxygen and water within the PEMFC. Performance improvements, ranked from highest to lowest, are TS-III > MD-G (Model-GA) > MD-P (Model-PSO) > TS-II > TS-I. Among the optimized models, TS-III (Topology Structure-III) exhibits the greatest increases in peak current density and peak power density, with improvement of 4.72% and 3.12%, respectively. When considering the relationship between performance improvement and pressure drop using the efficiency evaluation criterion (EEC), TS-II demonstrates the best overall performance.
