35 kV高压直挂大容量电池储能系统

为推动35 kV高压直挂电池储能系统(battery energy storage system,BESS)的实际应用,系统研究了35 kV高压直挂BESS的主电路参数设计、控制策略及相关控制参数的设计方法;并在MATLAB/Simulink中搭建了35 kV/10 MW/10 MWh系统的仿真模型,以验证所提设计方法及控制策略的正确性。研究结果表明:35 kV高压直挂BESS单机容量大,功率响应速度快,可对内部电池簇进行主动荷电状态均衡及故障冗余控制,系统效率和可靠性更高,能适应未来新能源大规模发展需求。

考虑SOC的混合储能功率分配与自适应虚拟惯性控制

电力电子化的直流配电网存在低惯性问题,不利于系统稳定运行。混合储能设备可向电网提供虚拟惯性,但不同类型的储能之间存在功率协调问题,并且储能的荷电状态(state of charge, SOC)对虚拟惯性的调节也有约束作用。针对上述问题,提出了一种自适应时间常数的分频控制策略,时间常数根据混合储能系统(hybridenergy storage system, HESS)的SOC而动态调整以改变功率分配。首先,通过分析储能SOC与虚拟惯性的关系,并考虑储能充放电极限问题,研究兼顾SOC、电压变化率以及电压幅值的自适应虚拟惯性控制策略,提高系统惯性。然后,建立控制系统的小信号模型,分析虚拟惯性系数对系统的影响。最后,基于Matlab/Simulink搭建直流配电网仿真模型,验证了所提控制策略能合理分配HESS功率,提高超级电容器利用率,改善直流电压与功率稳定性。

基于可逆固体氧化物电池的电氢耦合微电网全生命周期规划-运营研究

为促进实现“双碳”目标,新能源将成为未来能源供应的主体。考虑到高比例新能源对电力系统容量规划和调度运营带来的巨大挑战以及电氢能源需求量的持续增长对电力系统的影响,以微电网为研究对象,设计基于可逆固体氧化物电池的考虑源荷不确定性的电氢耦合微电网全生命周期规划-运营优化模型及其求解算法。首先,针对风光产电、电氢负荷等多种不确定因素,设计包含微电网全生命周期内各年份不同典型日的数据,以构成随机场景。其次,对电氢耦合微电网容量规划成本、全生命周期调度运营成本以及新能源年均渗透率等多个优化目标进行数学表达,并对各发电机组、可逆固体氧化物电池以及储氢库的规划-运营约束进行线性描述。然后,设计一种改进的增广ε约束算法求解模型的Pareto解集,并提出一种平衡决策方法从解集中获取最佳规划-调度方案。最后,仿真结果表明,所提方法能均衡各优化目标,在保证新能源高渗透率的同时提升电氢耦合微电网的可靠性以及规划-运营经济性。

从电池管理到电化学数字电源

电源技术的发展对绿色交通、规模化储能、智慧电网等领域具有重要作用。以电化学器件为代表的电化学电源具有反应机理复杂、多物理场、多尺度特性,同时工作过程中表现出强非线性、时变性及空间分布等特点,为电源的管理带来了挑战。本文以动力电池为对象,分别从模型、测量和管理三个方面阐述当前电池管理技术的研究现状及发展趋势,认为局限于本地的管理技术将逐渐走向全局的数字化管控,提出电化学数字电源的概念并诠释其内涵,旨在助力新能源汽车、氢电储能、新型电网、充电基础设施等电化学电源应用场景的发展。

光伏波动平抑下改进K-means的电池储能动态分组控制策略

针对电池储能系统(battery energy storage system,BESS)进行光伏波动平抑时寿命损耗高及荷电状态(state of charge,SOC)一致性差的问题,提出了光伏波动平抑下改进K-means的BESS动态分组控制策略。首先,采用最小最大调度方法获取光伏并网指令。其次,设计了改进侏儒猫鼬优化算法(improved dwarf mongoose optimizer,IDMO),并利用它对传统K-means聚类算法进行改进,加快了聚类速度。接着,制定了电池单元动态分组原则,并根据电池单元SOC利用改进K-means将其分为3个电池组。然后,设计了基于充放电函数的电池单元SOC一致性功率分配方法,并据此提出BESS双层功率分配策略,上层确定电池组充放电顺序及指令,下层计算电池单元充放电指令。对所提策略进行仿真验证,结果表明,所设计的IDMO具有更高的寻优精度及更快的寻优速度。所提BESS平抑光伏波动策略在有效平抑波动的同时,降低了BESS运行寿命损耗并提高了电池单元SOC的均衡性。

计及储能电池寿命衰减的居民小区光储优化配置

在居民小区配置光伏系统可减小电力系统的供电压力,配置储能装置能够减小光伏弃光率,同时还可以实现负荷的时空转移,减小负荷峰谷差。为使居民小区光储系统的配置更加合理,利用充放电次数和放电深度对储能电池寿命的影响,通过改进曲线拟合方法及线性分段处理方法,获得更加准确的曲线拟合函数和与原曲线更加贴合的分段线性函数,建立储能电池动态损耗模型;以光储系统年均净收益最大和负荷峰谷差最小为目标函数,对光储系统进行优化配置;最后使用不同权重求解方法得到光伏出力值及负荷需求值,采用多目标粒子群算法对在不同运行场景下的居民小区光储系统配置问题进行求解,并通过仿真对比分析不同运行场景下光储系统的运行策略。结果表明,居民小区储能系统在并网场景下的经济性和削峰填谷效果更佳,所采用模型合理有效,可为居民小区光储系统的规划建设提供参考。

一维多孔二氧化钛@碳纳米纤维复合材料的制备及储钠应用

通过静电纺丝法和浓碱水热刻蚀法原位制备出具有片状分枝结构的一维多孔二氧化钛@碳纳米纤维(P-TiO_(2)@CNFs)复合材料,并将其作为钠离子电池的负极材料。P-TiO_(2)@CNFs的片状分枝结构能够有效缩短离子扩散路径并增加电解液与活性物质的接触面积;多孔结构提供了更多的反应活性位点,从而加快了电荷转移动力学;二氧化钛与碳纳米纤维之间的化学键能够增加复合材料的结构稳定性。实验对P-TiO_(2)@CNFs的表面形貌、微观结构、晶体结构、比表面积、孔径、元素价态等进行了分析,并在新威尔电池测试系统上进行恒电流充放电测量和倍率性能测试,实验结果表明P-TiO_(2)@CNFs表现出优异的循环性能和倍率性能,在2.0A/g的电流密度下循环2000次仍能保持197mAh/g的比容量,在超大电流密度30.0A/g下电极仍然能够保持61.7mAh/g的比容量。

基于双向交错并联变换器的电池模拟器研究

动力锂离子电池测试既要考虑安全性、便捷性,也要考虑测试时间和硬件成本等因素。在保证测试精度前提下,将非线性电池模型与电力电子开关器件相结合,基于三阶RC等效电路模型,采用交错并联Buck-boost变换器作为电池模拟器的主电路拓扑,实现对真实动力电池的替代测试。首先分析了电池等效电路模型及其参数辨识原理。其次研究了电池模拟器工作原理和双向交错并联Buck-boost变换器控制策略,并设计了控制器参数。最后搭建了电池模拟器试验平台,试验结果表明该电池模拟器可以较高精度地实现对电池伏安外特性的模拟,可以满足对动力锂离子电池的测试需求。

用于一体化电极的碳布改性综述

由于碳布密度低、柔性高且导电导热性好,在电子器件中应用广泛。当碳布与其他材料复合时,为获得所需的性能,需对其进行改性处理。总结对当前用于电子器件中一体化电极的碳布进行改性的主要方法。从去浆、形貌处理和活性处理等3个方面进行介绍,并指出每种改性方法的优缺点和选用需考虑的要点。液相反应法对表面活性改变显著,但往往会降低电导率;热空气处理法对形貌改变显著,但操作过程复杂。液相氧化、热空气氧化和高温碳化相结合的改性效果可以更好,形貌改性和活性改性同时进行,可能会得到更好的综合性能。将碳布与活性物质直接复合制成一体化电极而完成改性处理,由于效率高可能成为改性技术的发展趋势。

光伏硅弃料制备锂离子电池硅负极的性能

纯硅的导电性差,且纳米化、非晶化技术成本高。光伏行业用硅的产业化程度高、导电性好,弃料可在锂离子电池硅基负极实现再利用。以光伏硅弃料为原料,采用机械球磨法制备纳米硅和非晶/纳米硅材料。制备的材料均具有较高的可逆比容量和稳定的循环性能,以0.2 C在0.005~0.900 V循环100次,纳米硅剩余的比容量为2 123.32 mAh/g,非晶/纳米硅剩余的比容量为1 367.70 mAh/g。

Ultra‑Transparent and Multifunctional IZVO Mesh Electrodes for Next‑Generation Flexible Optoelectronics

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic devices.Furthermore,they are crucial for applications in the fields of energy,display,healthcare,and soft robotics.Conducting meshes represent a promising alternative to traditional,brittle,metal oxide conductors due to their high electrical conductivity,optical transparency,and enhanced mechanical flexibility.In this paper,we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using selfcracking-assisted templates.Using this method,we produced an electrode with ultra-transparency(97.39%),high conductance(Rs=21.24Ωsq^(−1)),elevated work function(5.16 eV),and good mechanical stability.We also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics,organic light-emitting diodes,and flexible transparent memristor devices for neuromorphic computing,resulting in exceptional device performance.In addition,the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility,rendering them a promising option for application in flexible optoelectronics.

An Unprecedented Efficiency with Approaching 21%Enabled by Additive‑Assisted Layer‑by‑Layer Processing in Organic Solar Cells

Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition.This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture capability.This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.

Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Photo‑Energized MoS_(2)/CNT Cathode for High‑Performance Li–CO_(2)Batteries in a Wide‑Temperature Range

Li–CO_(2) batteries are considered promising energy storage systems in extreme environments such as Mars;however,severe performance degradation will occur at a subzero temperature owning to the sluggish reaction kinetics.Herein,a photo-energized strategy adopting sustainable solar energy in wide working temperature range Li–CO_(2) battery was achieved with a binder-free MoS_(2)/carbon nanotube(CNT)photo-electrode as cathode.The unique layered structure and excellent photoelectric properties of MoS_(2) facilitate the abundant generation and rapid transfer of photo-excited carriers,which accelerate the CO_(2) reduction and Li_(2)CO_(3) decomposition upon illumination.The illuminated battery at room temperature exhibited high discharge voltage of 2.95 V and mitigated charge voltage of 3.27 V,attaining superior energy efficiency of 90.2%and excellent cycling stability of over 120 cycles.Even at an extremely low temperature of−30℃,the battery with same electrolyte can still deliver a small polarization of 0.45 V by the photoelectric and photothermal synergistic mechanism of MoS_(2)/CNT cathode.This work demonstrates the promising potential of the photo-energized wide working temperature range Li–CO_(2) battery in addressing the obstacle of charge overpotential and energy efficiency.

Defect Engineering:Can it Mitigate Strong Coulomb Effect of Mg^(2+)in Cathode Materials for Rechargeable Magnesium Batteries?

Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.

Molecule‑Level Multiscale Design of Nonflammable Gel Polymer Electrolyte to Build Stable SEI/CEI for Lithium Metal Battery

The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious interfacial instability,which is a big challenge for design and application of nonflammable GPEs.Here,a nonflammable GPE(SGPE)is developed by in situ polymerizing trifluoroethyl methacrylate(TFMA)monomers with flame-retardant triethyl phosphate(TEP)solvents and LiTFSI–LiDFOB dual lithium salts.TEP is strongly anchored to PTFMA matrix via polarity interaction between-P=O and-CH_(2)CF_(3).It reduces free TEP molecules,which obviously mitigates interfacial reactions,and enhances flame-retardant performance of TEP surprisingly.Anchored TEP molecules are also inhibited in solvation of Li^(+),leading to anion-dominated solvation sheath,which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers.Such coordination structure changes Li^(+)transport from sluggish vehicular to fast structural transport,raising ionic conductivity to 1.03 mS cm^(-1) and transfer number to 0.41 at 30℃.The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm^(−2),and 4.2 V LiCoO_(2)|SGPE|Li battery delivers high average specific capacity>120 mAh g^(−1) over 200 cycles.This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.

“Zero‑Strain” NiNb_(2)O_(6) Fibers for All‑Climate Lithium Storage

Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.

Prussian Blue Analogue‑Templated Nanocomposites for Alkali‑Ion Batteries:Progress and Perspective

Lithium-ion batteries(LIBs)have dominated the portable electronic and electrochemical energy markets since their commercialisation,whose high cost and lithium scarcity have prompted the development of other alkali-ion batteries(AIBs)including sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).Owing to larger ion sizes of Na^(+)and K^(+)compared with Li^(+),nanocomposites with excellent crystallinity orientation and well-developed porosity show unprecedented potential for advanced lithium/sodium/potassium storage.With enticing open rigid framework structures,Prussian blue analogues(PBAs)remain promising self-sacrificial templates for the preparation of various nanocomposites,whose appeal originates from the well-retained porous structures and exceptional electrochemical activities after thermal decomposition.This review focuses on the recent progress of PBA-derived nanocomposites from their fabrication,lithium/sodium/potassium storage mechanism,and applications in AIBs(LIBs,SIBs,and PIBs).To distinguish various PBA derivatives,the working mechanism and applications of PBA-templated metal oxides,metal chalcogenides,metal phosphides,and other nanocomposites are systematically evaluated,facilitating the establishment of a structure–activity correlation for these materials.Based on the fruitful achievements of PBA-derived nanocomposites,perspectives for their future development are envisioned,aiming to narrow down the gap between laboratory study and industrial reality.

Alternative Strategy for Development of Dielectric Calcium Copper Titanate‑Based Electrolytes for Low‑Temperature Solid Oxide Fuel Cells

The development of low-temperature solid oxide fuel cells(LT-SOFCs)is of significant importance for realizing the widespread application of SOFCs.This has stimulated a substantial materials research effort in developing high oxide-ion conductivity in the electrolyte layer of SOFCs.In this context,for the first time,a dielectric material,CaCu_(3)Ti_(4)O_(12)(CCTO)is designed for LT-SOFCs electrolyte application in this study.Both individual CCTO and its heterostructure materials with a p-type Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2−δ)(NCAL)semiconductor are evaluated as alternative electrolytes in LT-SOFC at 450–550℃.The single cell with the individual CCTO electrolyte exhibits a power output of approximately 263 mW cm^(-2) and an open-circuit voltage(OCV)of 0.95 V at 550℃,while the cell with the CCTO–NCAL heterostructure electrolyte capably delivers an improved power output of approximately 605 mW cm^(-2) along with a higher OCV over 1.0 V,which indicates the introduction of high hole-conducting NCAL into the CCTO could enhance the cell performance rather than inducing any potential short-circuiting risk.It is found that these promising outcomes are due to the interplay of the dielectric material,its structure,and overall properties that led to improve electrochemical mechanism in CCTO–NCAL.Furthermore,density functional theory calculations provide the detailed information about the electronic and structural properties of the CCTO and NCAL and their heterostructure CCTO–NCAL.Our study thus provides a new approach for developing new advanced electrolytes for LT-SOFCs.

Optimization Strategies of Na_(3)V_(2)(PO_(4))_(3) Cathode Materials for Sodium‑Ion Batteries

Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.