Materials Today Physics最新文献_第9页

Construction of bifunctional MOF-based composite electrocatalysts promoting oxygen evolution reaction and glucose oxidation reaction and its kinetic deciphering 促进氧进化反应和葡萄糖氧化反应的双功能 MOF 基复合电催化剂的构建及其动力学解密

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-20 DOI: 10.1016/j.mtphys.2024.101601

Hongmei Yuan, Changyu Weng, Xinghua Zhang, Lungang Chen, Qi Zhang, Longlong Ma, Jianguo Liu

The climate crisis and the need for green and sustainable energy drive the rapid development of hydrogen production from water electrolysis. Improvements in the kinetics of the anode reaction, which governs the efficiency of water electrolysis, are essential for efficient hydrogen production and key to effectively addressing global environmental and energy challenges. Hence, we focus on improving the kinetics of the anode oxidation reaction. The multi-walled carbon nanotubes coupled with bimetallic organic framework (CoFe-MOF-74) composite electrocatalysts (CoFe-MOF-74@MWCNT) were fabricated for OER and the kinetically more favorable glucose oxidation reaction (GOR). Compared to commercial RuO₂, CoFe-MOF-74@MWCNT showed superior OER catalytic performance, exhibiting a lower overpotential (273 mV) and a lower Tafel slope (55 mV dec⁻¹) at a current density of 10 mA cm⁻². Moreover, after adding glucose to the anode, the potential required of 10 mA cm⁻² was only 1.291 V (vs. RHE), a reduction of 212 mV compared to the OER potential. This reduction in potential demonstrates the efficiency of our catalysts and signifies significant energy savings. The characterization results and theoretical calculations indicated that the superior OER/GOR performance of CoFe-MOF-74@MWCNT can be ascribed to the synergistic effect between MWCNT and the mixed metal nodes of the bimetallic organic framework. The doping of MWCNT promoted the catalyst charge transfer efficiency (R_ct was only 5.56 Ω) in the OER process. The mixed metal nodes of CoFe-MOF-74@MWCNT provided more active sites for the electrocatalytic reaction, and promoted the bond-breaking of critical intermediates in the oxidation process, significantly reducing the free energy of catalytic intermediates and accelerating reaction kinetics. This work provides a strategy for designing multifunctional electrocatalysts for OER and biomass small molecule oxidation and highlights the potential for significant energy savings in practical applications.

气候危机和对绿色可持续能源的需求推动了水电解制氢技术的快速发展。阳极反应制约着水电解的效率，改进阳极反应动力学是高效制氢的关键，也是有效应对全球环境和能源挑战的关键。因此，我们重点关注阳极氧化反应动力学的改进。我们制备了多壁碳纳米管与双金属有机框架（CoFe-MOF-74）复合电催化剂（CoFe-MOF-74@MWCNT），用于 OER 和动力学上更有利的葡萄糖氧化反应（GOR）。与商用 RuO2 相比，CoFe-MOF-74@MWCNT 表现出更优越的 OER 催化性能，在电流密度为 10 mA cm-2 时，过电位（273 mV）更低，塔菲尔斜率（55 mV dec-1）更低。此外，在阳极添加葡萄糖后，10 mA cm-2 所需的电位仅为 1.291 V（与 RHE 相比），比 OER 电位降低了 212 mV。电位的降低证明了我们催化剂的效率，同时也标志着显著的节能效果。表征结果和理论计算表明，CoFe-MOF-74@MWCNT 优异的 OER/GOR 性能可归因于 MWCNT 与双金属有机框架的混合金属节点之间的协同效应。MWCNT 的掺杂提高了 OER 过程中催化剂的电荷转移效率（Rct 仅为 5.56 Ω）。CoFe-MOF-74@MWCNT 的混合金属节点为电催化反应提供了更多的活性位点，促进了氧化过程中关键中间产物的断键，显著降低了催化中间产物的自由能，加速了反应动力学。这项工作为设计用于 OER 和生物质小分子氧化的多功能电催化剂提供了一种策略，并凸显了在实际应用中显著节能的潜力。

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引用次数: 0

Improving electromagnetic wave absorption performance by adjusting the proportion of brittle BCC phase in FeCoNiCr0.4Mnx high-entropy alloys 通过调整脆性 BCC 相在 FeCoNiCr0.4Mnx 高熵合金中的比例提高电磁波吸收性能

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-17 DOI: 10.1016/j.mtphys.2024.101596

Yuping Duan , Meiqi Li , Yuan Guo , Ning Zhu , Huifang Pang , Chenxu Dou

High-entropy alloys, as a novel type of absorber, exhibit exceptional electromagnetic modulation capabilities and significant potential for electromagnetic wave absorption. In this work, the FeCoNiCrMn high-entropy alloy absorbent prepared through a mechanical alloying process demonstrates a dual-phase solid solution structure comprising face-centered cubic (FCC) and body-centered cubic (BCC) phases. By varying the manganese (Mn) content in the system, it is possible to enhance the degree of crystallinity, maintain the integrity of the crystal structure, and effectively control the relative proportion of the BCC phase within the overall phase composition. This adjustment improves the brittleness of the sheet-like particles, reduces particle size, and significantly lowers the permittivity. When the molar ratio of Mn is 0.6, the sample exhibits improved impedance matching due to the optimal permittivity and permeability. Notably, the impedance matching and attenuation constant can also be balanced. At 6.42 GHz, the FeCoNiCr_0.4Mn_0.6 alloy powder achieves the maximum reflection loss of −48.49 dB at a matching layer thickness of 3 mm. When the matching thickness is reduced to 2 mm, it can effectively cover a frequency range of 8.7–14.1 GHz (effective absorption bandwidth of 5.4 GHz), along with a wide absorption bandwidth and high absorption efficiency.

高熵合金作为一种新型吸波材料，具有优异的电磁调制能力和巨大的电磁波吸收潜力。在这项研究中，通过机械合金化工艺制备的铁钴镍铬锰高熵合金吸波材料展示了由面心立方（FCC）相和体心立方（BCC）相组成的双相固溶体结构。通过改变体系中的锰（Mn）含量，可以提高结晶度，保持晶体结构的完整性，并有效控制 BCC 相在整个相组成中的相对比例。这种调整可以改善片状颗粒的脆性，减小颗粒尺寸，并显著降低介电常数。当锰的摩尔比为 0.6 时，由于具有最佳的介电常数和磁导率，样品的阻抗匹配得到改善。值得注意的是，阻抗匹配和衰减常数也可以达到平衡。在 6.42 GHz 频率下，FeCoNiCr0.4Mn0.6 合金粉末在匹配层厚度为 3 mm 时的最大反射损耗为 -48.49 dB。当匹配层厚度减小到 2 毫米时，它能有效覆盖 8.7-14.1 千兆赫的频率范围（有效吸收带宽为 5.4 千兆赫），同时具有较宽的吸收带宽和较高的吸收效率。

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引用次数: 0

Self-powered temperature pressure sensing arrays with stepped microcone structure and Bi2Te3-based films for deep learning-assisted object recognition 采用阶梯式微锥结构和基于 Bi2Te3 薄膜的自供电温度压力传感阵列，用于深度学习辅助物体识别

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-17 DOI: 10.1016/j.mtphys.2024.101588

Yaling Wang , Yue Sun , Wenqiang Li , Pan Li , Jing Wang , Pengcheng Zhu , Shiyang Qi , Jihua Tang , Yuan Deng

Flexible temperature-pressure bimodal sensing arrays can detect multiple types of information, including force and heat, making them crucial for applications such as object classification, human-machine interaction, and artificial intelligence. However, current sensors primarily focus on single-parameter and single-point measurements, while lacking a continuous and stable power supply. This study developed flexible, self-powered temperature-pressure sensing arrays by integrating a stepped microcone structure with thermoelectric materials. This stepped distribution microstructure design enabled effective pressure measurements across a wide range, with high sensitivity and fast response. Temperature-independent measurements were achieved synchronously over a wide temperature range (35–173 °C) by incorporating high-performance Bi₂Te₃-based thermoelectric films. These temperature and pressure sensing units can discern temperature and pressure stimuli without mutual interference. Furthermore, with the assistance of deep learning, these bimodal sensing arrays performed spatial mapping of temperature and pressure simultaneously, demonstrating their ability to identify different types of objects with an accuracy exceeding 98 %. Therefore, this study shows promise for advancing human-machine interaction, artificial intelligence, and self-powered electronic skins.

灵活的温度-压力双模传感阵列可以检测包括力和热在内的多种类型信息，因此对物体分类、人机交互和人工智能等应用至关重要。然而，目前的传感器主要侧重于单参数和单点测量，同时缺乏持续稳定的电源。本研究通过将阶梯式微锥结构与热电材料相结合，开发出了灵活、自供电的温度压力传感阵列。这种阶梯分布的微结构设计能够在很宽的范围内进行有效的压力测量，并具有高灵敏度和快速响应的特点。通过采用基于 Bi2Te3 的高性能热电薄膜，在较宽的温度范围（35-173 °C）内实现了与温度无关的同步测量。这些温度和压力传感装置能够辨别温度和压力刺激，而不会相互干扰。此外，在深度学习的辅助下，这些双模传感阵列还能同时进行温度和压力的空间映射，证明它们有能力识别不同类型的物体，准确率超过 98%。因此，这项研究有望推动人机交互、人工智能和自供电电子皮肤的发展。

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引用次数: 0

Fully degradable, highly sensitive pressure sensor based on bipolar electret for biomechanical signal monitoring 基于双极驻极体的完全可降解、高灵敏度压力传感器，用于生物力学信号监测

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-16 DOI: 10.1016/j.mtphys.2024.101597

Xingchen Ma , Yi Qin , Lian Zhou , Qianqian Hu , Xinhao Xiang , Heinz von Seggern , Sergey Zhukov , Alexander A. Altmann , Mario Kupnik , Wenxin Niu , Xiaoqing Zhang

In view of the global ecosystem crisis resulting from the ubiquitous electronic waste (e− and plastic waste), the engineering of advanced electronic devices from sustainable materials is gaining considerable attention. Nevertheless, the development of advanced, maybe even degradable electronics with comparable or even improved functionality remains a great challenge. In this article a fabrication process for a fully degradable, highly sensitive pressure sensor based on electrets is proposed enabling the creation of a universal platform for monitoring various biomechanical signals. The high sensitivity of the proposed biomechanical electret-based sensor utilizes electrostatic induction of highly deformable cellular polylactic acid (PLA) films with a serrated ripple structure and an improved bipolar charge storage capability. This biodegradable pressure sensor possesses competitive mechanical signal detection performance, obtaining a high pressure sensitivity (10 V/kPa), robust working stability (∼30,000 continuous cycles), short electromechanical response/recovery time (∼17 ms), and satisfactory heat resistance up to 60 °C. By tailoring the thickness of the encapsulation layer, the functional lifetime of the biomechanical sensor in physiological environment can be controlled effectively, facilitating adaptability to various implantable application scenarios. Altogether, the present work not only proposes an effective fabrication process for high-performance pressure sensors, but also provides new insight into the design of sustainable electronics with controllable lifetime thereby minimizing their environmental footprint. The developed sensor promises great potential in monitoring multiple biomechanical signals inside and outside the human body (e.g., body movements and physiological activities) as well as an environment-friendly realization of green electronics.

鉴于无处不在的电子废物（电子垃圾和塑料垃圾）所造成的全球生态系统危机，利用可持续材料制造先进电子设备的工程技术正日益受到广泛关注。然而，要开发出功能相当甚至更强的先进甚至可降解电子器件，仍然是一项巨大的挑战。本文提出了一种基于电子管的完全可降解、高灵敏度压力传感器的制造工艺，从而能够创建一个用于监测各种生物力学信号的通用平台。这种基于驻极体的生物力学传感器具有高灵敏度，它利用静电感应产生具有锯齿波纹结构和改进的双极电荷存储能力的高变形细胞聚乳酸（PLA）薄膜。这种可生物降解的压力传感器具有极具竞争力的机械信号检测性能，可获得较高的压力灵敏度（10 V/kPa）、强大的工作稳定性（∼30,000 次连续循环）、较短的机电响应/恢复时间（∼17 ms）和令人满意的耐热性（最高可达 60 °C）。通过调整封装层的厚度，可以有效控制生物力学传感器在生理环境中的功能寿命，从而适应各种植入应用场景。总之，本研究不仅为高性能压力传感器提出了一种有效的制造工艺，而且为设计寿命可控的可持续电子器件提供了新的见解，从而最大限度地减少了对环境的影响。所开发的传感器在监测人体内外的多种生物力学信号（如身体运动和生理活动）以及实现绿色电子产品的环境友好性方面具有巨大潜力。

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引用次数: 0

Bi2X (X = Ge, Sn) monolayers: Promising thermoelectric materials with ultra-low thermal conductivity Bi2X（X = Ge、Sn）单层：具有超低热导率的前景广阔的热电材料

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-14 DOI: 10.1016/j.mtphys.2024.101594

Minghao Lv , Nan Wu , Xiaofeng Fan , Weitao Zheng , David J. Singh

Thermoelectric materials can realize the direct conversion between heat and electricity, which provides a new strategy for waste heat treatment and power generation. The dimensionless value ZT determines the efficiency of the device. Here, we report a record ZT maximum of about 6.96 at 700 K by performing first-principles calculations on penta-Bi₂X (X = Ge, Sn) monolayers. We verified the stability of all systems and calculated the thermoelectric transport properties. The multiband energy degeneracy leads to large Seebeck coefficients, while the small phonon group velocity and strong anharmonic phonon scattering result in ultra-low thermal conductivity. Thus, in both systems, the higher ZT values are found. The high performance of Bi₂Ge and Bi₂Sn monolayers provide a new guidance for finding layered thermoelectric materials.

热电材料可实现热与电的直接转换，为废热处理和发电提供了一种新策略。无量纲值 ZT 决定了设备的效率。在此，我们通过对五-Bi2X（X = Ge，Sn）单层进行第一性原理计算，报告了在 700 K 时约 6.96 的 ZT 最大值。我们验证了所有系统的稳定性，并计算了热电传输特性。多带能量退化导致了较大的塞贝克系数，而较小的声子群速度和较强的非谐波声子散射则导致了超低的热导率。因此，在这两种体系中都能发现较高的 ZT 值。Bi2Ge 和 Bi2Sn 单层材料的高性能为寻找层状热电材料提供了新的指导。

引用次数: 0

NiFe pyrophosphate enables long-term alkaline seawater oxidation at an ampere-level current density 焦磷酸镍铁合金可在安培级电流密度下实现长期碱性海水氧化

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-13 DOI: 10.1016/j.mtphys.2024.101592

Yujie Yuan , Zixiao Li , Xun He , Hefeng Wang , Hong Tang , Xiaolan Tang , Qiuying Dai , Dongdong Zheng , Shengjun Sun , Yongsong Luo , Mohamed S. Hamdy , Fatma A. Ibrahim , Tingshuai Li , Bo Tang , Xuping Sun

Seawater electrolysis has potential for scalable hydrogen (H₂) production, yet anode corrosion by chloride ions (Cl⁻) remains a critical challenge. Herein, we present an amorphous NiFe pyrophosphate (P₂O₇⁴⁻) on Ni foam (NiFe-PPi/NF) for long-term alkaline seawater oxidation (ASO). Ex situ and in situ characterizations demonstrate that the in situ released P₂O₇⁴⁻ can act as an anion protective layer, effectively repelling Cl⁻ and safeguarding high-valence active metal sites during ASO. Through surface-anticorrosion design, NiFe-PPi/NF demonstrates stable operation at 1000 mA cm⁻² for over 1000 h with no loss in activity and requires a low overpotential of just 370 mV to achieve this industrial current density in alkaline seawater. This study offers a valuable strategy for developing corrosion-resistant anodes for ASO.

海水电解具有规模化制氢（H₂）的潜力，但氯离子（Cl-）对阳极的腐蚀仍然是一个严峻的挑战。在此，我们提出了一种泡沫镍（NiFe-PPi/NF）上的无定形焦磷酸镍铁（P2O74-），用于长期碱性海水氧化（ASO）。原位和原位表征结果表明，原位释放的 P2O74- 可作为阴离子保护层，在 ASO 过程中有效地排斥 Cl-，保护高价位活性金属位点。通过表面抗腐蚀设计，NiFe-PPi/NF 能在 1000 mA cm-2 的条件下稳定工作 1000 小时以上，且活性没有降低，只需 370 mV 的低过电位即可在碱性海水中达到这一工业电流密度。这项研究为开发 ASO 的抗腐蚀阳极提供了宝贵的策略。

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引用次数: 0

Grain recovery facilitated low-angle grain boundaries and texture for high-performance BiSbTe alloys 促进低角度晶界和纹理恢复的高性能碲镉铋合金的晶粒恢复

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-13 DOI: 10.1016/j.mtphys.2024.101591

Yuzheng Li , Feng Liu , Boyang Ying , Jiaying Liu , Yuzhou He , Kai Liu , Airan Li , Yongqing Wu , Zefeng Tang , Pengfei Nan , Binghui Ge , Chenguang Fu , Tiejun Zhu

Low-angle grain boundaries (LAGBs) bring an effective scattering of phonons while maintaining a weak effect on charge carrier transport, which could be utilized for enhancing the thermoelectric performance of solid materials. In the Bi₂Te₃-based materials fabricated by hot extrusion (HE) technique, however, the formation of the LAGBs is evitably accompanied by severe recrystallization, resulting in texture loss and hindering further zT improvement. Here, we demonstrate a feasible strategy utilizing the grain recovery to maintain dense LAGBs with high grain orientation by the optimized HE technique. As a result, a low thermal conductivity of about 1 W m⁻¹ K⁻¹ and a high power factor of 4.2 mW m⁻¹ K⁻² are achieved at 300 K for p-type Bi_0.5Sb_1.5Te₃ alloys, leading to a high room-temperature zT of 1.3. Further, with a decent flexural strength of 25.3 MPa, a 23-pair TE cooling module with the dice dimensions of 0.63 × 0.63 × 1.00 mm³ is assembled, which exhibits a maximum temperature difference of 87.8 K at a hot-side temperature T_h of 350 K. These results highlight the important role of grain-recovery manipulation in simultaneously optimizing the thermal and electrical properties toward high-performance Bi₂Te₃-based TE materials.

低角度晶界（LAGBs）能有效散射声子，同时对电荷载流子传输保持微弱的影响，可用于提高固体材料的热电性能。然而，在通过热挤压（HE）技术制造的基于 Bi2Te3 的材料中，LAGB 的形成必然伴随着严重的再结晶，从而导致纹理损失，阻碍了 zT 的进一步提高。在此，我们展示了一种利用晶粒回复的可行策略，通过优化的 HE 技术保持高晶粒取向的致密 LAGB。因此，p 型 Bi0.5Sb1.5Te3 合金在 300 K 时的热导率低至约 1 W m-1 K-1，功率因数高至 4.2 mW m-1 K-2，室温 zT 高达 1.3。此外，由于挠曲强度达到 25.3 MPa，还组装出了一个 23 对 TE 冷却模块，其尺寸为 0.63×0.63×1.00 mm3，在 350 K 的热侧温度 Th 下显示出 87.8 K 的最大温差。这些结果凸显了晶粒回复操作在同时优化基于 Bi2Te3 的高性能 TE 材料的热性能和电性能方面的重要作用。

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引用次数: 0

Superconducting memory and trapped magnetic flux in ternary lanthanum polyhydrides 三元镧系多氢化物中的超导记忆和捕获磁通量

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-13 DOI: 10.1016/j.mtphys.2024.101595

Dmitrii V. Semenok , Andrey V. Sadakov , Di Zhou , Oleg A. Sobolevskiy , Sven Luther , Toni Helm , Vladimir M. Pudalov , Ivan A. Troyan , Viktor V. Struzhkin

Superconducting memory is a promising technology for data storage because of its speed, high energy efficiency, non-volatility, and compatibility with quantum computing devices. However, the need for cryogenic temperatures renders superconducting memory an extremely expensive and specialized device. Ternary lanthanum polyhydrides, due to their high critical temperatures of 240–250 K, represent a convenient platform for studying effects associated with superconductivity in disordered granular systems. In this work, we investigate trapped magnetic flux and memory effects in recently discovered lanthanum-neodymium (La,Nd)H₁₀ and lanthanum-scandium (La,Sc)H₁₂ superhydrides at a pressure of 175–196 GPa. We use a steady magnetic field of a few Tesla (T) and strong pulsed fields up to 68 T to create the trapped flux state in the compressed superhydrides. We find a clockwise hysteresis of magnetoresistance in cerium CeH_9-10 and lanthanum-cerium (La,Ce)H_10+x polyhydrides, a characteristic feature of granular superconductors. A study of the current-voltage characteristics and voltage-temperature curves of the samples with trapped magnetic flux indicates a significant memory effect in La-Sc polyhydrides already at 225–230 K.

超导存储器具有速度快、能效高、不易挥发以及与量子计算设备兼容等优点，是一种前景广阔的数据存储技术。然而，由于需要低温，超导存储器成为一种极其昂贵的专用设备。三元镧系多氢化物的临界温度高达 240-250 K，是研究无序颗粒体系超导效应的便捷平台。在这项工作中，我们研究了最近发现的镧-钕（La,Nd）H10 和镧-钪（La,Sc）H12 超水化合物在 175-196 GPa 压力下的捕获磁通和记忆效应。我们使用几特斯拉（T）的稳定磁场和高达 68 T 的强脉冲磁场，在压缩超氢中创造出困通态。我们在铈-CeH9-10 和镧-铈 (La,Ce)H10+x 多氢化物中发现了顺时针磁阻滞后现象，这是粒状超导体的一个特征。对样品的电流-电压特性和电压-温度曲线的研究表明，在 225-230 K 时，镧铈多氢化物中就已经存在显著的记忆效应。

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引用次数: 0

Impact of an annealing atmosphere on band-alignment of a plasma-enhanced atomic layer deposition-grown Ga2O3/SiC heterojunction 退火气氛对等离子体增强原子层沉积生长的 Ga2O3/SiC 异质结带排列的影响

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-12 DOI: 10.1016/j.mtphys.2024.101593

Yi Shen , An-Feng Wang , Hong-Ping Ma , Xin Qi , Qilong Yuan , Mingyang Yang , Mengting Qiu , Bingxue Zhang , Nan Jiang , Qingchun Jon Zhang

Gallium oxide (Ga₂O₃) has attracted much attention because of its notable advantages, including its low cost and a high critical breakdown field. In this study, atomic layer deposition was used to deposit high-quality Ga₂O₃ onto a SiC substrate with high thermal conductivity. The band arrangement of the Ga₂O₃/SiC heterojunction was investigated by modulating oxygen vacancies using different post-annealing atmospheres. The results demonstrated that recrystallization of Ga₂O₃ resulted in a good crystalline state because of the rearrangement of Ga and O atoms following high-temperature annealing. Simultaneously, the roughness of all annealed samples increased. X-ray photoelectron spectroscopy analysis revealed a significant reduction of oxygen vacancy content in samples that were annealed in an oxygen atmosphere; this is attributed to the replacement of oxygen vacancies by oxygen atoms. Conversely, oxygen vacancies increased in an oxygen-free environment. The band offsets (valence band, conduction band) were respectively determined to be (−1.03 eV, 0.5 eV), (−0.63 eV, 0.9 eV), (−1.39 eV, 0.16 eV), and (−1.32 eV, 0.22 eV) for the as-deposited sample and annealed samples with O₂, N₂, and Ar atmospheres. Finally, the impact that various ratios of oxygen vacancies have on the energy band structure of Ga₂O₃ was studied using first-principles calculations. Calculations on heterojunctions confirmed that the introduction of oxygen vacancies reduced the potential barrier at the interface and promoted the movement of electrons. Thus, this study provides valuable insights for the design and application of Ga₂O₃/SiC heterojunction devices.

氧化镓（Ga2O3）具有成本低、临界击穿场强等显著优点，因此备受关注。本研究采用原子层沉积法在具有高热导率的碳化硅衬底上沉积高质量的 Ga2O3。通过使用不同的退火后气氛调节氧空位，研究了 Ga2O3/SiC 异质结的能带排列。结果表明，由于高温退火后 Ga 原子和 O 原子的重新排列，Ga2O3 的再结晶产生了良好的结晶状态。同时，所有退火样品的粗糙度都有所增加。X 射线光电子能谱分析表明，在氧气气氛中退火的样品中氧空位含量显著减少，这是因为氧原子取代了氧空位。相反，氧空位在无氧环境中有所增加。经测定，在氧气、氮气和氩气气氛中萃取的样品和退火的样品的能带偏移（价带、导带）分别为（-1.03 eV，0.5 eV）、（-0.63 eV，0.9 eV）、（-1.39 eV，0.16 eV）和（-1.32 eV，0.22 eV）。最后，利用第一原理计算研究了不同比例的氧空位对 Ga2O3 能带结构的影响。对异质结的计算证实，氧空位的引入降低了界面的势垒，促进了电子的移动。因此，这项研究为 Ga2O3/SiC 异质结器件的设计和应用提供了宝贵的见解。

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引用次数: 0

Highly stretchable, low-hysteresis, and antifreeze hydrogel for low-grade thermal energy harvesting in ionic thermoelectric Supercapacitors 用于离子热电超级电容器中低级热能收集的高拉伸、低滞后和抗冻水凝胶

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-11-10 DOI: 10.1016/j.mtphys.2024.101589

Wanyu Qian , Shuanglin Jia , Penglu Yu , Ke Li , Mingxuan Li , Jinle Lan , Yuan-Hua Lin , Xiaoping Yang

Efficient harvest of low-grade waste heat in the environment through thermoelectric materials represents a promising strategy to address the current energy crisis. In practical applications, the mechanical properties of thermoelectric materials are crucial for their lifespan and operational environment. In this study, we designed a series of ionic thermoelectric hydrogels, PAM/CMC-xLiCl, with high mechanical properties. These hydrogels are formed by a dual network structure composed of polyacrylamide (PAM) and sodium carboxymethyl cellulose (CMC), with LiCl serving as the conductive material. At room temperature, the optimal Seebeck coefficient and ionic conductivity of the hydrogels can reach 2.96 mV K⁻¹ and 36.51 mS cm⁻¹, respectively. Based on the physical entanglement, hydrogen bonding, and chemical crosslinking of the polymer chains within the ionic hydrogels, which demonstrate outstanding mechanical properties (elongation at break >1300 %, fracture toughness >1700 kJ m⁻³), maintaining 95 % resilience under a large strain of 400 %. Furthermore, due to the hydration properties of LiCl, the ionic hydrogels exhibit excellent freeze resistance and the capability to absorb moisture for self-regeneration upon drying. Lastly, the fabricated ionic thermoelectric supercapacitor can generate a thermoelectric voltage of 0.182 V under a ΔT of 12 K, with a power density of 6.68 mW m⁻², showing promising prospects for application in waste heat harvest fields.

通过热电材料有效收集环境中的低品位废热，是解决当前能源危机的一项大有可为的战略。在实际应用中，热电材料的机械性能对其寿命和运行环境至关重要。在本研究中，我们设计了一系列具有高机械性能的离子热电水凝胶 PAM/CMC-xLiCl。这些水凝胶由聚丙烯酰胺（PAM）和羧甲基纤维素钠（CMC）组成的双重网络结构构成，并以氯化锂作为导电材料。室温下，水凝胶的最佳塞贝克系数和离子电导率分别可达 2.96 mV K-1 和 36.51 mS cm-1。基于离子水凝胶中聚合物链的物理缠结、氢键和化学交联，该水凝胶具有出色的机械性能（断裂伸长率为 1300%，断裂韧性为 1700 kJ m-3），在 400% 的大应变下仍能保持 95% 的回弹性。此外，由于氯化锂的水合特性，离子水凝胶表现出卓越的抗冻性和吸湿能力，可在干燥后自我再生。最后，所制备的离子热电超级电容器在 12 K 的 ΔT 下可产生 0.182 V 的热电电压，功率密度为 6.68 mW m-2，在余热收集领域的应用前景十分广阔。

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引用次数: 0