Understanding the in situ fluorination of high capacity cathode materials for rechargeable batteries

Organic carbonyl compounds are regarded as promising candidates for next-generation rechargeable batteries in terms of low cost, environmental protection, and high capacity. The carbonyl utilization is a key issue to...

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Mn3O4@MnS composite nanoparticles as cathode materials for aqueous rechargeable Zn ion batteries

Functional Materials Letters ◽

10.1142/s1793604721430025 ◽

2021 ◽

pp. 2143002

Author(s):

Xingyuan Gao ◽

Haodong Li ◽

Xianshuo Cao ◽

Xihong Lu

Keyword(s):

Electrical Conductivity ◽

Energy Density ◽

Thermal Treatment ◽

Cathode Materials ◽

High Performance ◽

High Capacity ◽

Good Stability ◽

Composite Nanoparticles ◽

Capacity Retention

Exploring high-capacity and stable cathode materials for aqueous rechargeable Zn ion batteries (ZIBs) is highly attractive but challenging. Herein, we present a kind of Mn3O4@MnS heterostructured nanoparticle as a robust ZIB cathode. These Mn3O4@MnS nanoparticles are facilely synthesized by in-situ transformation of MnO2 under sulfidation thermal treatment. Owing to the heterostructured architecture and improved electrical conductivity, the as-obtained Mn3O4@MnS nanoparticles afford a stable capacity of 128.3 mA h g[Formula: see text] at 2 mA cm[Formula: see text] and good stability of more than 65% capacity retention after 1000 cycles. Additionally, a remarkably energy density of 184.72 Wh kg[Formula: see text] is also achieved by the assembled Zn//Mn3O4@MnS battery. This work paves the way for constructing Mn-based heterostructures as high-performance cathodes in aqueous ZIBs.

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Rapid mechanochemical synthesis of polyanionic cathode with improved electrochemical performance for Na-ion batteries

Nature Communications ◽

10.1038/s41467-021-23132-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Xing Shen ◽

Quan Zhou ◽

Miao Han ◽

Xingguo Qi ◽

Bo Li ◽

...

Keyword(s):

Energy Storage ◽

Electrochemical Performance ◽

Mechanochemical Synthesis ◽

Cathode Materials ◽

Industrial Application ◽

Synthesis Process ◽

In Situ Fabrication ◽

Stationary Energy ◽

Carbon Coated

AbstractNa-ion batteries have been considered promising candidates for stationary energy storage. However, their wide application is hindered by issues such as high cost and insufficient electrochemical performance, particularly for cathode materials. Here, we report a solvent-free mechanochemical protocol for the in-situ fabrication of sodium vanadium fluorophosphates. Benefiting from the nano-crystallization features and extra Na-storage sites achieved in the synthesis process, the as-prepared carbon-coated Na3(VOPO4)2F nanocomposite exhibits capacity of 142 mAh g−1 at 0.1C, higher than its theoretical capacity (130 mAh g−1). Moreover, a scaled synthesis with 2 kg of product was conducted and 26650-prototype cells were demonstrated to proof the electrochemical performance. We expect our findings to mark an important step in the industrial application of sodium vanadium fluorophosphates for Na-ion batteries.

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In situ XRD and operando spectra-electrochemical investigation of tetragonal WO3-x nanowire networks for electrochromic supercapacitors

NPG Asia Materials ◽

10.1038/s41427-021-00319-7 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Shen Wang ◽

Hongbo Xu ◽

Tingting Hao ◽

Peiyuan Wang ◽

Xiang Zhang ◽

...

Keyword(s):

Reaction Mechanism ◽

Electronic Device ◽

High Capacity ◽

Optical Modulation ◽

Function Evaluation ◽

Dual Function ◽

Electrochemical Performances ◽

Electrochemical Cycling ◽

Nanowire Networks

AbstractElectrochromic supercapacitors (ESCs) are appealing for smart electronic device applications due to their advantages of dual-function integration. Unfortunately, the synchronous dual-function evaluation and the essential reaction mechanism are ambiguous. Herein, we constructed a 3D WO3-x nanowire networks/fluorine-doped tin oxide (WO3-x NWNs/FTO) bifunctional electrode for ESCs by a solvothermal self-crystal seeding method. The synchronous correspondence relationship between the optical and electrochemical performances of the WO3-x NWNs/FTO electrode was explored using an operando spectra-electrochemical characterization method. It reveals an excellent areal capacity of 57.57 mF cm−2 with a high corresponding optical modulation (ΔT) of 85.05% and high optical-electrochemical cycling stability. Furthermore, the synergistic reaction mechanism between the Al3+ ion intercalation behavior and the surface pseudocapacitance reaction during electrochemical cycling is revealed utilizing in situ X-ray diffraction. Based on these results, an ESC device was constructed by pairing WO3-x/FTO as the cathode with V2O5 nanoflowers/FTO (V2O5 NFs/FTO) as the anode, which simultaneously deliver high capacity and large optical modulation. Moreover, the energy storage level of the ESC device could be visually monitored by rapid and reversible color transitions in real time. This work provides a promising pathway to developing multi-functional integrated smart supercapacitors.

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