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Cerium, a unique rare earth element, possesses a relatively high abundance, low cost, and high redox voltage, making it an attractive candidate for redox flow batteries. However, the sluggish kinetics and corrosion nature of the Ce3+/Ce4+ electrolyte result in overpotential and degradation of carbon felt (CF) electrodes, which hinders the development of cerium‐based flow batteries. Therefore, it is essential to develop an electrode with high catalytic activity and corrosion resistance to the Ce3+/Ce4+ electrolyte. Herein, a TiC/TiO2 coated carbon felt (TiC/TiO2‐CF) electrode is proposed. Remarkably, the TiC/TiO2 coating effectively minimizes the exposure of the CF to the highly corrosive cerium electrolyte, consequently enhancing the electrode's corrosion resistance. Additionally, X‐ray photoelectron spectroscopy and high‐resolution transmission electron microscopy characterizations reveal the formation of a heterojunction between TiC and TiO2, which significantly enhances the redox reaction kinetics of the Ce3+/Ce4+ redox couple. Eventually, the practical application of TiC/TiO2‐CF catalytic electrode in a Ce–Fe flow battery is demonstrated. This study sheds light on the synthesis conditions of the TiC/TiO2‐CF electrode, elucidates its heterojunction structure, and presents a novel Ce–Fe flow battery system. [ABSTRACT FROM AUTHOR]

Zinc‐ion batteries (ZIBs) have attracted intensive attention due to the low cost, high safety, and abundant resources. However, up to date, challenges still exist in searching for cathode materials with high working potential, excellent electrochemical activity, and good structural stability. To address these challenges, microstructure engineering has been widely investigated to modulate the physical properties of cathode materials, and thus boosts the electrochemical performances of ZIBs. Here, the recent research efforts on the microstructural engineering of various ZIB cathode materials are mainly focused upon, including composition and crystal structure selection, crystal defect engineering, interlayer engineering, and morphology design. The dependency of cathode performance on aqueous electrolyte for ZIB is further discussed. Finally, future perspectives and challenges on microstructure engineering of cathode materials for ZIBs are provided. It is aimed to provide a deep understanding of the microstructure engineering effect on Zn2+ storage performance. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) are expected to be a promising commercial alternative to lithium-ion batteries (LIBs) for large-scale and low-cost electrical energy storage applications in the near future. Despite this, the absence of a suitable negative electrode material hinders their development. In this contribution, we synthesized monodispersed hard carbon spherules (HCS) from an abundant biomass of sucrose, and investigated the influence of the carbonization temperature on the microstructure and electrochemical performance. The initial coulombic efficiency of the HCS was increased to 83% by coating its surface with soft carbon through the pyrolysis of toluene. Interestingly, the plateau capacity at the low potential region increased with increasing carbonization temperature. The HCS carbonized at 1600 °C showed the highest plateau capacity (220 mA h g -1) and excellent cycling performance with a capacity retention of 93% after 100 cycles. When coupled with an air-stable P2-Na2/3Ni1/3Mn2/3O2 positive electrode, the full cell exhibited a high initial coulombic efficiency of 76%, a mean operating voltage of 3.5 V and excellent cycling performance. The theoretical energy density of this system was estimated to be 200 W h kg-1. These promising properties are believed to be close to the level required for practical applications. [ABSTRACT FROM AUTHOR]

Highlights from the article: Keywords: high energy density; Na3V2(PO4)3; redox flow batteries; redox-targeting; sodium batteries In article number 1901188, Yong-Sheng Hu, Qing Wang and co-workers report a flow battery based on the redox-targeting reactions of methylphenothiazine and fluorenone with Na SB 3 sb V SB 2 sb (PO SB 4 sb ) SB 3 sb as the sole capacity booster in both cathodic and anodic compartments. High energy density, redox flow batteries, sodium batteries, Na3V2(PO4)3, redox-targeting.