Search

Prussian blue analogues (PBAs) have attracted extensive attention as cathode materials in sodium‐ion batteries (SIBs) due to their low cost, high theoretical capacity, and facile synthesis process. However, it is of great challenge to control the crystal vacancies and interstitial water formed during the aqueous co‐precipitation method, which are also the key factors in determining the electrochemical performance. Herein, an antioxidant and chelating agent co‐assisted non‐aqueous ball‐milling method to generate highly‐crystallized Na2‐xFe[Fe(CN)6]y with hollow structure is proposed by suppressing the speed and space of crystal growth. The as‐prepared Na2‐xFe[Fe(CN)6]y hollow nanospheres show low vacancies and interstitial water content, leading to a high sodium content. As a result, the Na‐rich Na1.51Fe[Fe(CN)6]0.87·1.83H2O hollow nanospheres exhibit a high initial Coulombic efficiency, excellent cycling stability, and rate performance via a highly reversible two‐phase transition reaction confirmed by in situ X‐ray diffraction. It delivers a specific capacity of 124.2 mAh g−1 at 17 mA g−1, presenting ultra‐high rate capability (84.1 mAh g−1 at 3400 mA g−1) and cycling stability (65.3% capacity retention after 1000 cycles at 170 mA g−1). Furthermore, the as‐reported non‐aqueous ball‐milling method could be regarded as a promising method for the scalable production of PBAs as cathode materials for high‐performance SIBs. [ABSTRACT FROM AUTHOR]

Over the past decades, porous carbonaceous and carbon‐incorporated composites have aroused tremendous attention owing to their unique properties such as high surface area, excellent accessibility to active sites, tunable morphologies and structures, and superior mass transport and diffusion. They have been widely investigated and applied in various fields, such as energy storage, absorption, water filtration, drug delivery, catalysis, and sensing. In the energy storage area, rechargeable sodium‐ion batteries (SIBs) have attracted tremendous attention as the next‐generation power plants for large‐scale energy storage systems (EESs). However, their low energy density and power density, as well as their poor cyclability, are still the main challenges for SIBs, especially for the anode, which acts as a bottleneck. With the incorporation of appropriate porous carbonaceous materials, the disadvantages of large volume shrinkage and low electron conductivity of alloying‐ and conversion‐based anode materials have been significantly alleviated. This review points out and summarizes the most recent developments in synthesis strategies and morphology control of porous carbonaceous materials and the corresponding carbonaceous‐material‐incorporated high performance anodes for SIBs. Furthermore, the remaining challenges associated with these composites and effective routes to enhance their performance are discussed. [ABSTRACT FROM AUTHOR]

With the current rapid growth of commercial applications for flexible and wearable optoelectronic devices, flexible power sources are very much in demand. Herein, a facile strategy to grow cobalt nanoparticles encapsulated in nitrogen‐doped carbon nanotube arrays on flexible carbon fiber cloth as self‐supported electrodes for high‐performance flexible zinc–air batteries is developed. Benefiting from high electrical conductivity and multiple active sites as well as free polymer binder, the self‐supported electrode exhibits excellent electrocatalytic activity. The maximum power density of a zinc–air battery using the self‐supported electrode as air cathode is higher than that of the zinc–air battery with Pt/C+IrO2 as air electrode. Furthermore, the zinc–air battery can be stably operated under external stress without obvious loss of the electrochemical performance. This work opens up a new pathway for the rational design of flexible electrodes for high‐performance flexible power sources. [ABSTRACT FROM AUTHOR]