Efforts to improve performance, like energy and power density of electrochemical energy storage devices (batteries, capacitors, and super-capacitors), are being made using a range of experimental and computational tools. The most common strategy involves exploring new material chemistries, developing advanced synthesis routes, and advanced ways to integrate these materials into device architectures. Although it is desirable to evaluate the performance of such efforts at a fixed cell format, not all studies conduct testing across the same cell formats. Specific performance normalized per mass of active material has been adopted as a universal indicator of performance, but it is not a reliable way to compare across cell formats. We propose a new mass normalization, i.e., the mass of electrochemical participants, to calculate specific performance. This new specific performance makes it possible to efficiently compare the efficacy of materials, synthesis, and cell assembly across different cell formats. We developed a framework to comprehensively report materials, synthesis, and cell assembly, and performance data, which facilitates succinctly reporting all performance indicators, including charge discharge curves over all cyclic stability assessments. The new specific performance and mass of the electrochemical participants per unit area of the electrode allows us to create a calculator to estimate performance at any commercial device-level cell format from measured data at the laboratory-level cell. The new specific performance also helps in optimizing the coating thickness and the loading of the active material. The framework can be adapted by journals to facilitate the reporting of data in a comprehensive way. Leveraging this framework, we have also compiled a database (hosted at https://power.tattvasar.com/) by extracting pertinent data from existing literature.
Towards Quantitative Analysis of Deuterium Absorption in Ferrite and Austenite during Electrochemical Charging by Comparing Cyclic Voltammetry and Cryogenic Transfer Atom Probe Tomography
Electrochemical properties of Na$_{0.66}$V$_4$O$_{10}$ nanostructures as cathode material in rechargeable batteries for energy storage applications
我们报道了Na $_{0.66}$ V $_4$ O $_{10}$纳米结构作为可充电电池阴极材料的电化学性能。室温X射线衍射图的Rietveld精修显示具有C2/m空间群的单斜相。所制备的半电池的循环伏安曲线在~3.1和2.6~V处呈现氧化还原峰,这是由于V $^{5+/4+}$之间的两相转变反应,并且可以归属于Na离子的单步脱嵌/嵌入。我们观察到良好的循环稳定性,在电流密度为3和50 mA g $^{-1}$下,放电比容量(相对于Na $^+$ /Na测量)分别在80($\pm$ 2)和30($\pm$ 2)mAh g $^{-1}$之间。还用Li阳极测试了Na $_{0.66}$ V $_4$ O $_{10}$电极的电化学性能,其显示出比Na更高的容量,但衰减更快。利用密度泛函理论,我们计算了Na空位的形成能;在材料的本体中为3.37~eV,在(100)表面上为2.52~eV,这强调了纳米结构的重要性。
Unraveling the storage mechanism of Na$_{3}$V$_{2-x}$Ni$_x$(PO$_4$)$_2$F$_3$/C cathodes for sodium-ion batteries through electrochemical, {\it operando} X-ray diffraction and microscopy studies
本研究结合 EIS、GITT、CV、operando XRD 与原位同步辐射 TXM,揭示 Ni 掺杂 Na₃V₂(PO₄)₂F₃/C 正极的储钠机制、扩散动力学及长循环稳定性。
BaMF$_4$ (M = Mn, Co, Ni): New Electrode Materials for Hybrid Supercapacitor with Layered Polar Structure
为了追求基于具有氧化还原反应或吸附/脱附效应的法拉第电荷转移的超级电容器的高电化学性能,电解质离子到电极材料中的嵌入效率是具有额外体积贡献的超过纯表面容量的关键先决条件。在这里,我们报告了层状钡过渡金属氟化物,BaMF_4(M = Mn,Co,Ni)是一系列新的电极材料应用于标准的三电极配置。得益于电解质离子的有效浸润,这些材料具有显著的比电容。电化学表征表明,BaMF 4电极在循环伏安图中既表现出电容行为,又表现出法拉第氧化还原反应,并具有良好的充放电循环储电能力和循环稳定性。特别是BaCoF_4在电流密度为0.6 A g ~(-1)时,其比电容最高,达到360 F g ~(-1),即使其颗粒尺寸远远超过纳米级。此外,第一性原理计算揭示了可能的潜在机制。
ZnO/ZnS heterostructures as hole reservoir to boost Ni foam energy storage performance
University of Catania(卡塔尼亚大学);IMM-CNR(意大利国家研究委员会材料研究所);Catalan Institute of Nanoscience and Nanotechnology (ICN2)(加泰罗尼亚纳米科学和技术研究所);CSIC(西班牙国家研究委员会);BIST(巴塞罗那科学技术研究院);ICREA(加泰罗尼亚卓越研究员)
Improved Electrochemical Performance and Diffusion kinetics by Boron-doping in Na$_{0.66}$Mn$_{0.8}$Fe$_{0.2}$O$_{2}$ Layered Cathodes for Sodium-Ion Batteries
Indian Institute of Technology Delhi(印度德里理工学院);Hindu College, University of Delhi(德里大学印度教学院);Indian Institute of Technology Delhi-Abu Dhabi(印度德里理工学院阿布扎比分校)
Ni modified Fe3O4(001) surface as a simple model system for understanding the Oxygen Evolution Reaction
电化学水分解是一种以化学燃料的形式储存可再生能源的环保技术。在地球资源丰富的第一行过渡金属基催化剂中,Ni-Fe混合氧化物在碱性介质中有效且低成本地催化析氧反应(OER)方面表现出了良好的性能,但Fe和Ni阳离子在OER机理中的协同作用尚不清楚。在这项工作中,我们报告了添加Ni如何改变模型氧化铁催化剂的反应性,该模型氧化铁催化剂基于Ni沉积并结合在磁铁矿Fe 3 O 4(001)单晶中,使用超高真空中的表面科学技术的组合,如低能电子衍射(LEED)、X射线光电子能谱学(XPS)、低能离子散射(LEIS)、和扫描隧道显微镜(STM),以及在空气中的原子力显微镜(AFM),和电化学方法,例如循环伏安法(CV)和在碱性介质中的电化学阻抗谱(EIS)。当顶表面呈现20- 40%范围内的Fe:Ni组成比时,观察到OER活性的显著改善,这与对于粉末催化剂所观察到的良好一致。此外,在电解质中表面老化三天后,观察到OER过电位下降。在较高的Ni负载,AFM显示的增长归因于一个(氧)-氢氧化物相,根据CV测量,似乎不相关的表面活性对OER的一个新的阶段。EIS表明,OER前体物种上观察到的清洁和Ni改性的表面是相似的,Fe为中心,但形成在较低的过电位时,表面Fe:Ni的比例进行了优化。
Facile preparation of CuCo$_2$S$_4$/Cu$_7$S$_4$ nanocomposites as high-performance cathode materials for rechargeable magnesium batteries
寻找高效、高性能的镁离子二次电池正极材料是探索可持续能源技术的迫切需要。然而,大多数用于RMBs的阴极材料通常遭受由结构崩溃引起的低倍率容量和差的循环性能。本文首次采用溶剂热法合成了纳米尺寸的CuCo $_2$ S $_4$ /Cu $_7$ S $_4$三元复合材料,并探讨了其作为锂离子电池正极材料的镁离子存储行为。电化学测试结果表明,CuCo $_2$ S $_4$ /Cu $_7$ S $_4$复合材料在10 mA/g和300 mA/g电流密度下的首次放电容量分别为256 mAh/g和123 mAh/g。此外,在300 mA/g下实现了出色的长期循环稳定性,300次循环后可逆容量为106 mA/g,库仑效率约为99%。CuCo $_2$ S $_4$ /Cu $_7$ S $_4$的纳米球结构、三元组成和赝电容存储行为是其优异电化学性能的主要原因。本研究结果表明,通过一种简单有效的方法制备的CuCo $_2$ S $_4$ /Cu $_7$ S $_4$纳米复合材料是一种有前途的储能/转换用锂离子电池阴极材料。