电活性聚合物发电基本原理及应用研究

剖析了电活性聚合物在静电场中机械能和电能相互转换的内部机理,主要针对电活性聚合物发电原理进行分析研究.在不考虑能量损耗的理想前提下,探讨电活性聚合物在发电过程中3种能量循环过程.最后,采用丹佛斯生产的电活性聚合物(DEAP)材料,建立了电活性聚合物发电机实验装置平台,分析恒电荷状态下收集能量过程.试验验证了电活性聚合物发电原理.实验结果表明,作为新型智能材料的电活性聚合物在发电应用领域前景广阔.     

基于声学黑洞的压电俘能结构系统仿真与优化

薄板结构中的声学黑洞(ABH)可降低弯曲波的相速度,同时增大振幅,在声学黑洞区域产生高能量密度和能量聚集效应,与压电俘能结构相结合,可提升能量转化效率。该文首先建立了基于声学黑洞的压电俘能结构的有限元模型,对比分析了均匀板及声学黑洞结构的动能密度及电压输出特性;基于有限元法推导了压电振子等效电路模型,并通过Multisim软件建立压电俘能全系统等效电路耦合模型,确定了负载电路最优电阻,提高系统俘能效率。     

风能收集型摩擦纳米发电机研究进展

有效地将自然界中的能量转换为电能对于构建环境友好型社会具有重要意义。摩擦纳米发电机(Triboelectric Nanogenerator,TENG)是一种新型的机械能-电能转换装置,可实现将微弱机械能高效地转换为电能。在自然界众多的机械能中,风能因其分布广和储存量大而受到广泛关注。近年来,将风能高效率地转换为电能是TENG技术的研发重点之一。研究人员对此展开了细致的研究工作,获得大量研究进展。一般说来,风能收集型TENG的研究内容主要包括器件结构优化、摩擦起电材料的物理与化学改性以及电源管理电路设计优化。针对这些研究内容,详细介绍了近年来TENG在收集风能方面的研究进展,剖析存在的问题,并对其未来的应用和发展进行了展望。     

不同边界条件下d_(15)模式压电俘能器的俘能性能

该文考虑了全夹持和半夹持边界条件分别对d15模式压电悬臂梁俘能性能的影响。基于铁木辛柯梁理论建立了d15模式压电双晶片悬臂梁装置理论模型,并制作了半夹持结构悬臂梁的实验装置模型,测量了其在不同频率和不同负载电阻下的压电俘能性能。结果表明,设计的半夹持结构悬臂梁俘能器具有更优异的俘能性能和在低频环境下俘能的潜能。     

Elastic-Connection and Soft-Contact Triboelectric Nanogenerator with Superior Durability and Efficiency

Triboelectric nanogenerator (TENG) has received tremendous attention in ambient energy harvesting, especially for ocean wave energy. However, the technology is generally challenged to obtain excellent durability and high efficiency simultaneously, which primarily overshadows their further industrial-scale applications. Here, a dual-mode and frequency multiplied TENG with ultrahigh durability and efficiency for ultralow frequency mechanical energy harvesting via the elastic connection and soft contact design is proposed. By introducing the spring and flexible dielectric fluff to the novel pendulum-like structural design, the surface triboelectric charges of TENG are replenished in soft contact mode under the intermittent mechanical excitation, while the robustness and durability are enhanced in non-contact working mode. The fabricated TENG results in a continuous electrical output for 65 s by one stimulus with a high energy conversion efficiency, as well as negligible change of output performance after a total of 2 000 000 cycles. Moreover, integrated with the power management circuit, the TENG array is demonstrated to drive the electronics by effectively harvesting wind and water wave energy as a sustainable energy source. This work paves a new pathway to enhance the robustness, durability, and efficiency of the TENG that resolves the bottleneck of its practical applications and industrialization.     

Field Enhanced Robust Droplet Electricity Generation

Harvesting low grade hydrodynamic energy is attracting growing interest. Droplet generators have recently emerged as promising harvesting devices. However, toward practical utilization, their power density and energy conversion efficiency still warrant further improvement. In addition, the performance of droplet generators typically degrades when in contact with ambient water, significantly limiting their applications considering that they, by definition, are constantly exposed to water. This work reports a field-enhanced droplet electricity generator (FE-DEG) that significantly address these challenges. Using the field effect induced by a bias voltage to store high volumetric charge in the dielectric layer, the amount of charge that transfers during droplet impinging is significantly increased, which simultaneously improves the instantaneous power density and energy conversion efficiency. In addition, the performance of the generator can be reliably set by the external bias and remains stable after repeated immersion in bulk water, and even in some harsh chemical conditions. It is expected that this work may also inspire other robust energy harvesting devices.     

MSMA振动能量采集器的设计与实现

采用智能材料磁控形状记忆合金(MSMA)将机械振动能量转换成电能为无线电子设备供电已备受关注。该文利用MSMA的维拉利效应(逆磁致伸缩效应)分析了MSMA振动能量采集器工作原理,计算并确定了振动能量采集系统的磁轭、线圈、保护系统、固定装置的尺寸和性能参数。利用ANSYS软件对系统进行了仿真,验证了各部分结构参数和材料选型的正确性。在此基础上,设计制作了MSMA振动能量采集器样机,搭建了MSMA振动能量采集器实验平台,进行了振动力激振实验,得到了在不同输入频率和应力大小条件下感应电压的输出曲线,实验和仿真结果表明,利用MSMA材料可将机械振动能量转化为电能,为振动能量收集利用提供了参考依据。     

Triboelectric Nanogenerator Networks Integrated with Power Management Module for Water Wave Energy Harvesting

Ocean waves are one of the most promising renewable energy sources for large‐scope applications. Recently, triboelectric nanogenerator (TENG) network has been demonstrated to effectively harvest water wave energy possibly toward large‐scale blue energy. However, the absence of effective power management severely restricts the practicability of TENGs. In this work, a hexagonal TENG network consisting of spherical TENG units based on spring‐assisted multilayered structure, integrated with a power management module (PMM), is constructed for harvesting water wave energy. The output performance of the TENG network is found to be determined by water wave frequencies and amplitudes, as well as the wave type. Moreover, with the implemented PMM, the TENG network could output a steady and continuous direct current (DC) voltage on the load resistance, and the stored energy is dramatically improved by up to 96 times for charging a capacitor. The TENG network integrated with the PMM is also applied to effectively power a digital thermometer and a wireless transmitter. The thermometer can constantly measure the water temperature with the water wave motions, and the transmitter can send signals that enable an alarm to go off once every 10 s. This study extends the application of the power management module in the water wave energy harvesting.     

基于可再生能量协作的雾无线接入网络资源分配

针对雾无线接入网络(Fog Radio Access Network,F-RAN)中能耗开销巨大的问题,提出了一种基于能量收集(Energy Harvesting,EH)约束的资源分配算法,从联合模式选择与功率分配两个方面进行了研究.首先建立传输模型和能量采集模型,根据功率约束和电费支出约束建立最优化问题;再使用分枝定界法对通信模式进行选择,利用吞吐量注水法对不同传输模式下的发射功率进行分配.仿真结果表明,提出的基于可再生能量协作的F-RAN的吞吐量和电网能量效率均高于传统F-RAN,具有经济和环境双重效益.     

Spherical Triboelectric Nanogenerators Based on Spring‐Assisted Multilayered Structure for Efficient Water Wave Energy Harvesting

Making use of water wave energy at large is one of the most attractive, low‐carbon, and renewable ways to generate electric power. The emergence of triboelectric nanogenerator (TENG) provides a new approach for effectively harvesting such low‐frequency, irregular, and “random” energy. In this work, a TENG array consisting of spherical TENG units based on spring‐assisted multilayered structure is devised to scavenge water wave energy. The introduction of spring structure enhances the output performance of the spherical TENG by transforming low‐frequency water wave motions into high‐frequency vibrations, while the multilayered structure increases the space utilization, leading to a higher output of a spherical unit. Owing to its unique structure, the output current of one spherical TENG unit could reach 120 µA, which is two orders of magnitude larger than that of previous rolling spherical TENG, and a maximum output power up to 7.96 mW is realized as triggered by the water waves. The TENG array fabricated by integrating four units is demonstrated to successfully drive dozens of light‐emitting diodes and power an electronic thermometer. This study provides a new type of TENG device with improved performance toward large‐scale blue energy harvesting from the water waves.     

Emerging Role of the Band‐Structure Approach in Biohybrid Photovoltaics: A Path Beyond Bioelectrochemistry

Emulation of natural photosynthesis is central to modern photovoltaic research targeting sustainable and economic ways of solar energy harvesting. Natural photosynthetic systems have succeeded in efficiently harvesting solar energy which is key to the sustenance of life on earth. With numerous advances in understanding the structure and function of the natural photosystems, the last decade has witnessed new perspectives in developing bioinspired photovoltaics. Interestingly, organic photovoltaics (OPVs) adopting photosynthetic design principles and biophotovoltaics (BPVs) adopting solid‐state device architectures have now converged at a juncture. Several reports in recent years point to a new scope of improvement in OPVs and BPVs stemming from mutual inspiration. At this juncture, there are new perspectives by which a BPV can be designed that were previously limited only to conventional optoelectronics. Treating natural pigment–proteins as optically and electronically functional materials in any photovoltaic design, from the band‐theory viewpoint, is a promising direction for advancing BPVs beyond the boundaries of bioelectrochemistry. This article presents an overview of selected reports on BPVs in the last few years utilizing new design concepts based on band‐theory and its associated principles. In light of this, the scope of the band‐structure approach in BPVs is discussed, eliciting prospective research directions.     

四边简支板结构的挠电能量采集研究

为了研究正挠电效应在能量采集方面的应用，该文针对四边简支矩形板结构建立了挠电俘能器模型。 首先推导了在点激励作用下四边简支矩形板的动态响应；其次根据正挠电效应建立了由动态应变梯度引起的能量采集理论，并推导出外部负载电阻两端的输出电压与功率表达式；最后分析了不同的参数，如板的模态、激励位置、 挠电片尺寸、厚度与位置及负载电阻等对输出电压与功率的影响。研究结果表明，不同振动模态、贴片位置及挠电片厚度等均影响挠电能量采集的输出功率，该分析结果对优化板结构挠电俘能器的能量输出有实际意义。     

宽频压电振动发电机阵列特性分析与实验

利用压电振动发电机可实现环境振动能量到电能的转化,压电振动发电机阵列可实现较宽频带的振动能量收集,压电振动发电机的特性研究通常采用机械分析方法,该文采用电路分析方法针对压电振动发电机阵列的串、并联方式进行了特性分析,利用电子电路仿真软件PSPICE对串、并联不同连接方式下压电发电机阵列的内阻及负载电压与负载功率进行了比较分析,最后设计了一台压电发电机阵列并进行了实验分析,验证了特性分析的正确性。     

A Swing Self-Regulated Triboelectric Nanogenerator for High-Entropy Ocean Breaking Waves Energy Harvesting

Multidirectional irregular breaking wave is the most prominent feature of the ocean surface and bears tremendous amounts of sustainable high-entropy energy. However, the commercial utilization and harvesting efficiency are very limited low due to its low-frequency and low-amplitude. Here, a swing self-regulated triboelectric nanogenerator (SSR-TENG) is proposed, which can convert collected low-grade breaking waves energy into electrical energy by regulating the oscillation frequency and resonance effect. Benefiting from simple and efficient structural strategy, SSR-TENG outputs a peak power of 0.14 mW under wave height range of 6–11 cm, that the open-circuit voltage, short-circuit current and transferred charge increases is 5.8, 4, and 3.7 times compared to without self-regulated design, respectively. This work gives a practical solution to the problems faced by harvesting high-entropy ocean breaking waves energy, which exhibits large potential for building the self-powered ocean assessment and meteorology system in the future.     

Stretchable Electrode Based on Laterally Combed Carbon Nanotubes for Wearable Energy Harvesting and Storage Devices

Carbon nanotubes (CNTs) are a promising material for use as a flexible electrode in wearable energy devices due to their electrical conductivity, soft mechanical properties, electrochemical activity, and large surface area. However, their electrical resistance is higher than that of metals, and deformations such as stretching can lead to deterioration of electrical performances. To address these issues, here a novel stretchable electrode based on laterally combed CNT networks is presented. The increased percolation between combed CNTs provides a high electrical conductivity even under mechanical deformations. Additional nickel electroplating and serpentine electrode designs increase conductivity and deformability further. The resulting stretchable electrode exhibits an excellent sheet resistance, which is comparable to conventional metal film electrodes. The resistance change is minimal even when stretched by ≈100%. Such high conductivity and deformability in addition to intrinsic electrochemically active property of CNTs enable high performance stretchable energy harvesting (wireless charging coil and triboelectric generator) and storage (lithium ion battery and supercapacitor) devices. Monolithic integration of these devices forms a wearable energy supply system, successfully demonstrating its potential as a novel soft power supply module for wearable electronics.     

Heterogeneous MXene/PS-b-P2VP Nanofluidic Membranes with Controllable Ion Transport for Osmotic Energy Conversion

Membrane-based osmotic power harvesting is a strategy for sustainable power generation. 2D nanofluids with high ion conductivity and selectivity are emerging candidates for osmotic energy conversion. However, the ion diffusion under nanoconfinement is hindered by homogeneous 2D membranes with monotonic charge regulation and severe concentration polarization, which results in an undesirable power conversion performance. Here, an asymmetric nanochannel membrane with a two-layered structure is reported, in which the angstrom-scale channels of 2D transition metal carbides/nitrides (MXenes) act as a screening layer for controlling ion transport, and the nanoscale pores of the block copolymer (BCP) are the pH-responsive arrays with an ordered nanovoid structure. The heterogeneous nanofluidic device exhibits an asymmetric charge distribution and enlarged 1D BCP porosity under acidic and alkaline conditions, respectively; this improves the gradient-driven ion diffusion, allowing a high-performance osmotic energy conversion with a power density of up to 6.74 W m⁻² by mixing artificial river water and seawater. Experiments and theoretical simulations indicate that the tunable asymmetric heterostructure contributes to impairing the concentration polarization and enhancing the ion flux. This efficient osmotic energy generator can advance the fundamental understanding of the MXene-based heterogeneous nanofluidic devices as a paradigm for membrane-based energy conversion technologies.     

Segmented Swing-Structured Fur-Based Triboelectric Nanogenerator for Harvesting Blue Energy toward Marine Environmental Applications

Reducing carbon emissions to realize carbon neutrality is crucial to the environmental protection, and developing clean and renewable energy sources is an effective means to achieve this goal. Triboelectric nanogenerators (TENGs) provide a promising energy technology for converting the abundant renewable ocean wave energy on the earth surface. In this work, a segmented swing-structured fur-based TENG (SSF-TENG) is designed and fabricated to harvest low frequency water wave energy. The introduction of soft and dense rabbit furs reduces the frictional resistance and material wear, and the design and optimization of segmented structures further enhance the output performance of TENG. The use of ultra-lubricated bearings makes the SSF-TENG achieve an extended period of energy harvesting of more than 5 min after one triggering, with a total energy conversion efficiency of up to 23.6%. Under the real water wave triggering, the SSF-TENG can deliver a maximum peak power of 6.2 mW and an average power of 0.74 mW. Furthermore, through effective water wave energy harvesting by the SSF-TENG or array, self-powered marine environmental applications are successfully demonstrated, which establishes a solid foundation for large-scale blue energy harvesting and realization of smart oceans.     

High-Performance Flexible Schottky DC Generator via Metal/Conducting Polymer Sliding Contacts

Dynamic Schottky direct-current (DC) generators hold great promise for ambient mechanical energy harvesting as it overcomes the low-current output limitation in conventional approaches. However, the lack of a fundamental understanding of DC generation in conducting polymer-based Schottky generators has hindered their application for self-powered wearable and implantable electronics. Here, a high-performance, flexible Schottky DC generator with metal/conducting polymer sliding contact system is demonstrated, which exhibits a large current density (J) up to 20 A m^–2 for single contact geometry and a scaled-up DC output reaching 200 µA (J = 0.73 A m^–2) and 0.8 V. The design of flexibility in such a Schottky DC generator is inherited from the long-chain polymer concept, leading to the demonstration of a variety of device configuration of free-standing thin film, supported thin film and nanocomposite prototype toward practical applications. It is revealed that the sliding junctions may exhibit a different mechanical energy conversion mechanism compared to the compressive conducting polymer Schottky junctions. It is also proven that the magnitude and polarity of DC generation is determined by the Schottky contact formation and interfacial electric field. The concept of a flexible Schottky generator not only shows great promise for next-generation, self-powered wearable devices, but also provides potential mechanisms for developing novel wearable sensors.     

Whirling‐Folded Triboelectric Nanogenerator with High Average Power for Water Wave Energy Harvesting

Ocean wave energy, as one of the most abundant resources on the earth, is a promising energy source for large‐scale applications. Triboelectric nanogenerators (TENGs) provide a new strategy for water wave energy harvesting; however, its average performance in realistic water wave conditions is still not high. In this work, a whirling‐folded TENG (WF‐TENG) with maximized space utilization and minimized electrostatic shielding is constructed by 3D printing and printed circuit board technologies. The flexible vortex structure responds easily to multiform wave excitation with improved oscillation frequency. A standard water wave tank is established to generate controllable water waves to characterize the device performance. It is found to be determined by wave conditions and internal structure, which is also revealed by a theoretical dynamical analysis. The WF‐TENG can produce a maximum peak power of 6.5 mW and average power of 0.28 mW, which can power a digital thermometer to operate constantly and realize self‐powered monitoring on the TENG network to prevent possible damage in severe environments. Moreover, a self‐charge‐supplement WF‐TENG network is proposed to improve the output performance and stability. This study provides an effective strategy for improving the average power and characterizing the performance of spherical TENG towards large‐scale blue energy.     

单晶压电振子结构二维优化设计

为优化单晶压电振子结构,提高其在特定工作环境要求下的能量转化效率,建立了输出电荷量的振子形状函数的理论模型。综合考虑发电效能、工作面积、结构体积及紧凑度在实际应用中的重要度,通过对各个因子的无量纲化处理,建立了单晶压电振子的评价函数。以某特定风动能环境下的风力压电发电机为例,对压电振子进行了二维优化设计,理论计算结果表明,相比于等截面矩形悬臂梁式压电振子,优化结构的发电量提高了51.8%,工作面积及结构体积分别减小了11.75%,30.41%。与一维优化的梯形压电振子相比,综合性能也有一定提高。但利用有限元软件对优化压电振子进行振型分析发现,其固有频率相比于矩形振子有所提高,使得在较低振动频率环境中的应用受到一定限制。