Energies
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2022
·Vol. 15
·期 8
·2732
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IF 3.252
Xia Sheng,Chunyu Ru,Honghui Zhao,Shouyi Jin,Bowen Wang,Yupeng Wang,Linghai Han,Kui Jiao
Hydrogen starvation leads to the extreme deterioration of fuel cell performance due to the induced voltage reversal and carbon corrosion in the anode catalyst layer (ACL) and gas diffusion layer. In this paper, reversal-tolerant anodes (RTAs) with different ACL configurations are proposed, where IrOx/C is used as a water electrolysis catalyst. Experimental results show that the separate IrOx/C catalyst layer of MEA samples, layered reversal-tolerant catalyst-coated membrane (layered-RTA), and reversal-tolerant gas diffusion electrode (GDE-RTA) significantly enhance the reversal tolerance and cell performance compared to conventional anode and common RTA consisting of a homogeneous catalyst layer mixed with IrOx/C and Pt/C (hybrid-RTA). Of these, GDE-RTA possessed a reversal tolerance time of 86 min, a power density of 1.42 W cm−2, and a minimum degradation rate of 2.4 mV min−1, suggesting it to be the best RTA structure. Cyclic voltammetry and electrochemical impedance spectrum were used to detect the properties of each sample. Additionally, the degradation mechanisms of the three RTAs are thoroughly investigated and discussed by means of microstructural characterization through scanning electron microscopy and transmission electron microscopy. This work provides novel ideas for the fabrication of a robust RTA by tuning the ACL configuration, which is practical for the commercialization of fuel cells.Keywords:fuel cell;hydrogen starvation;reversal tolerance;catalyst layer configuration;degradation mechanism
研究领域:
能源科学
·
材料科学
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产品关联
DOI
高影响因子
Energy & Environmental Materials
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2023
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IF 15
Kejun Xu,Liuying Wang,Chaoqun Ge,Long Wang,Bin Wang,Zhuo Wang,Chuanwei Zhang,Gu Liu
NiO, an anodic electrochromic material, has applications in energy-saving windows, intelligent displays, and military camouflage. However, its electrochromic mechanism and reasons for its performance degradation in alkaline aqueous electrolytes are complex and poorly understood, making it challenging to improve NiO thin films. We studied the phases and electrochemical characteristics of NiO films in different states (initial, colored, bleached and after 8000 cycles) and identified three main reasons for performance degradation. First, Ni(OH) 2 is generated during electrochromic cycling and deposited on the NiO film surface, gradually yielding a NiO@Ni(OH) 2 core–shell structure, isolating the internal NiO film from the electrolyte, and preventing ion transfer. Second, the core–shell structure causes the mode of electrical conduction to change from first- to second-order conduction, reducing the efficiency of ion transfer to the surface Ni(OH) 2 layer. Third, Ni(OH) 2 and NiOOH, which have similar crystal structures but different b -axis lattice parameters, are formed during electrochromic cycling, and large volume changes in the unit cell reduce the structural stability of the thin film. Finally, we clarified the mechanism of electrochromic performance degradation of NiO films in alkaline aqueous electrolytes and provide a route to activation of NiO films, which will promote the development of electrochromic technology.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Zeyu Wu,Zhenhua Wang,Jing Zhang,Zhe Bai,Lina Zhao,Ruilong Li,Zhanfeng Yang,Yu Bai,Kening Sun
The graphite/lithium metal hybrid anode shows great potential for achieving high-specific-energy lithium batteries. Despite the “dead lithium” problem caused by repeated stripping and deposition of Li component based on a conversion reaction, the degradation mechanism, based on intercalation reaction, of graphite in a hybrid anode is generally ignored. In this contribution, through in situ X-ray diffraction and in situ Raman analysis, we reveal that hysteresis and the mixed-phase state of graphite during deintercalation play a critical role in hybrid battery degradation. On the other hand, we successfully mitigated graphite degradation and increased the reversible capacity of the hybrid anode by introducing an inorganic-rich solid electrolyte interface. Remarkably, the hybrid anode (30% higher specific capacity compared to graphite) exhibits an average coulombic efficiency of 99.11% and retains 96.13% of initial capacity over 120 cycles. This work sheds new light on the advancement of high-specific-energy lithium secondary batteries.
研究领域:
材料科学
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电化学
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能源存储
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产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Longkui Zheng,Yang Xiang,Dawei Zheng,Ning Luo
In this study, we systematically investigate the triboelectric performance degradation of polytetrafluoroethylene (PTFE)-based triboelectric nanogenerators (TENGs) under high–low temperature cycling and humidity variations, a critical yet underexplored challenge in extreme environmental applications. Under accelerated aging conditions spanning 0–300 thermal cycles and 0–90% RH, PTFE films demonstrated progressively worsening electrical output, their short-circuit current declining steadily from 7.2 to 4.6 μA, alongside an open-circuit voltage drop from 400 to 240 V. Surface characterization via scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy reveals that thermal cycling induces microstructural defects and chemical oxidation, where oxygen content replaced C–F bonds with weaker electron-accepting groups (C–O, C═O). This oxidative degradation reduced PTFE’s electron affinity and directly impaired charge transfer efficiency in TENGs. To address performance unpredictability, an improved extreme learning machine algorithm is developed, achieving 100% accuracy in real-time classification of PTFE aging states by analyzing triboelectric signals. Furthermore, paired with pristine PTFE, aged PTFE modified surface states enable a 21.8-fold power output enhancement and outperform conventional configurations. These findings establish a mechanistic framework linking thermal-humidity aging to triboelectric decay while proposing machine-learning-driven predictive maintenance strategies for TENGs in aerospace, energy systems, and autonomous devices operating in harsh environments.
研究领域:
材料科学
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纳米技术
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电气工程
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表面科学
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机器学习
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环境测试
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高分子科学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）