Noticeable pseudo‐capacitance behavior out of charge storage mechanism (CSM) has attracted intensive studies because it can provide both high energy density and large output power. Although cyclic ...voltammetry is recognized as the feasible electrochemical technique to determine it quantitatively in the previous works, the results are inferior due to uncertainty in the definitions and application conditions. Herein, three successive treatments, including de‐polarization, de‐residual and de‐background, as well as a non‐linear fitting algorithm are employed for the first time to calibrate the different CSM contribution of three typical cathode materials, LiFePO4, LiMn2O4 and Na4Fe3(PO4)2P2O7, and achieve well‐separated physical capacitance, pseudo‐capacitance and diffusive contributions to the total capacity. This work can eliminate misunderstanding concepts and correct ambiguous results of the pseudo‐capacitance contribution and recognize the essence of CSM in electrode materials.
Well‐separated physical capacitance, pseudo‐capacitance, and diffusive capacity are achieved from the CV curves of typical electrode materials for metal‐ion batteries after three successive treatments including de‐polarization, de‐residual and de‐background as well as non‐linear fitting calculation, offering a more rational and reliable method to calculate the pseudo‐capacitance contribution.
Hierarchical carbon framework wrapped Na3V2(PO4)3 (HCF‐NVP) is successfully synthesized through chemical vapor deposition on pure Na3V2(PO4)3 particles. Electrochemical experiments show that the ...HCF‐NVP electrode can deliver a large reversible capacity (115 mA h g−1 at 0.2 C), superior high‐rate rate capability (38 mA h g−1 at 500 C), and ultra‐long cycling stability (54% capacity retention after 20 000 cycles).
Sodium‐ion batteries (SIBs) are considered to be a low‐cost complement or competitor to Li‐ion batteries for large‐scale electric energy storage applications; however, their development has been less ...successful due to the lack of suitable host materials to enable reversible Na+ insertion reactions. Prussian blue analogs (PBAs) appear to be attractive candidates for SIB cathodes because of their open channel structure, compositional and electrochemical tunability. In this paper, the authors present a comprehensive review on the recent advances in the development of PBA frameworks as SIB cathodes with particular attention to the structure‐performance correlation of the PBA materials, and discuss the possible strategies to address the problems present in the SIB applications of PBAs. Also, the development of the PBA frameworks for the insertion cathodes of other monovalent and multivalent ions is briefly introduced, with the aim of providing a new insight into the design and development of new host materials for the next‐generation advanced batteries.
This paper reviews the recent progress on the structural and electrochemical studies of Prussian blue analog (PBA) frameworks as Na+ insertion cathodes with a focus on the correlations between the lattice structure and the ion insertion properties of PBAs. Possible strategies for the future development of PBAs for sodium‐ion batteries and other multivalent ion batteries are proposed.
Turning on your P/C: An amorphous phosphorus/carbon (a‐P/C) composite was synthesized using simple mechanical ball milling of red phosphorus and conductive carbon powders. This material gave an ...extraordinarily high sodium ion storage capacity of 1764 mA h g−1 (see graph) with a very high rate capability, showing great promise as a high capacity and high rate anode material for sodium ion batteries.
Sodium‐ion batteries (SIBs) are now being actively developed as low cost and sustainable alternatives to lithium‐ion batteries (LIBs) for large‐scale electric energy storage applications. In recent ...years, various inorganic and organic Na compounds, mostly mimicked from their Li counterparts, have been synthesized and tested for SIBs, and some of them indeed demonstrate comparable specific capacity to the presently developed LIB electrodes. However, the lack of suitable cathode materials is still a major obstacle to the commercial development of SIBs. Here, we present a brief review on the recent developments of SIB cathodes, with a focus on low cost and high energy density materials (> 450 Wh kg−1 vs Na) together with discussion of their Na‐storage mechanisms. The considerable differences in the structural requirements for Li‐ and Na‐storage reactions mean that it is not sufficient to design SIB cathode materials by simply mimicking LIB materials, and therefore great efforts are needed to discover new materials and reaction mechanisms to further develop variable cathodes for advanced SIB technology. Some directions for future research and possible strategies for building advanced cathode materials are also proposed here.
Recent developments in cathode materials with a high energy density (> 450 Wh kg−1) for sodium‐ion batteries (SIBs) are reviewed and their Na‐storage mechanisms discussed. Some possible strategies for building advanced cathode materials are also proposed.
3D graphene decorated NaTi2(PO4)3 (NTP@rGO) is successfully synthesized through a facile spray‐drying method. This NTP@rGO material can deliver high reversible capacity (130 mAh g−1 at 0.1 C), ...superior high‐rate rate capability (38 mAh g−1 at 200 C) and long cycling stability (77% capacity retention after 1000 cycles), suggesting its applicability as a high rate and cycle‐stable anode for the development of high‐power and long cycle life sodium ion batteries for energy storage applications.
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•Structure and electrochemical mechanism of Na0.44MnO2 is summarized.•The relationship between synthesis, morphology and property is discussed.•The remaining challenges and feasible ...strategies for Na0.44MnO2 are commented.
Sodium-ion battery has been widely studied because of its abundant sodium resources and expectable electrochemical performance. The unique tunnel Na0.44MnO2 has attracted wide attention as one of the available cathode materials because of its low cost, as well as long cycle stability and rate capability in the non-aqueous and aqueous batteries. During the past decades, much efforts have been made to improve the electrochemical performance of the Na0.44MnO2. This review concisely describes the research progress of Na0.44MnO2 cathode for both non-aqueous and aqueous sodium-ion batteries, mainly focuses on the crystal structure, morphology, charge–discharge mechanism and influence of different synthesis and modification methods on the morphology and electrochemical performance. In addition, the main opportunities and challenges in this field are briefly commented and discussed.
A honeycomb layered Na3Ni2SbO6 is synthesized as a cathode for sodium‐ion batteries. This new host material exhibits a high capacity of 117 mA h g−1, a remarkable cyclability with 70% capacity ...retention over 500 cycles at a 2C rate, and a superior rate capability with >75% capacity delivered even at a very high rate of 30 C (6000 mA g−1). These results open a new perspective to develop high‐capacity and high‐rate Na‐ion batteries for widespread electric‐energy‐storage applications.
Electrochromism has received increasing attention due to its unique electrochromic feature and the induced applications. This review provides an overview on the recent developments in the synthesis ...and application of the electrochromic metal oxides in smart windows, display devices, e‐skins, and multifunctional energy storage devices. The main cathodic and anodic electrochromic metal oxides are surveyed here, with the discussion of representative examples in details. The current state‐of‐the‐art research activities of the derived multifunctional electrochromic devices are highlighted, i.e., material systems, components, structures, morphology, the resulting performance, etc. Major challenges and potential solutions are also discussed. Additionally, the future perspective on the development trends in electrochromic metal oxides and the commercialization of relevant devices is also proposed.
The current state‐of‐the‐art research activities on electrochromic metal oxides and the built devices and applications are reviewed. It includes comprehensive literature reviews and critical comments with representative and detailed examples. Application‐specific research challenges, future design considerations, and development directions are also discussed.
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