Iron anode-based aqueous electrochemical energy storage devices: Recent advances and future perspectives

The ever-growing demands for green and sustainable power sources for ap-plications in grid-scale energy storage and portable/wearable devices have enabled the continual development of advanced aqueous electrochemical energy storage(EES)systems.Aqueous batteries and supercapacitors made of iron-based anodes are one of the most promising options due to the remark-able electrochemical features and natural abundance,pretty low cost and good environmental friendliness of ferruginous species.Though impressive ad-vances in developing the state-of-the-art ferruginous anodes and designing various full-cell aqueous devices have been made,there still remain key issues and challenges on the way to practical applications,which urgently need discussing to put forwards possible solutions.In this review,rather than focusing on the detailed methods to optimize the iron anode,electrolyte,and device performance,we first give a comprehensive review on the charge storage mechanisms for ferruginous anodes in different electrolyte systems,as well as the newly developed iron-based aqueous EES devices.The deep in-sights,involving the inherent failure mechanisms and corresponding modification/optimization strategies toward iron anodes for the development of high-performance aqueous EES devices,will then be discussed.The advances in applying iron-based aqueous EES devices for emerging fields such as flexible/wearable electronics and functionalized building materials will be further outlined.Last,future research trends and perspectives for maximizing the potential of current iron anodes and devices as well as exploiting brand-new iron-based aqueous EES systems are put forward.

Performance of iron-air battery with iron nanoparticle-encapsulated C-N composite electrode

Highly efficient and stable iron electrodes are of great significant to the development of iron-air battery(IAB).In this paper,iron nanoparticle-encapsulated C–N composite(NanoFe@CN)was synthesized by pyrolysis using polyaniline as the C–N source.Electrochemical performance of the NanoFe@CN in different electrolytes(alkaline,neutral,and quasi-neutral)was investigated via cyclic voltammetry(CV).The IAB was assembled with NanoFe@CN as the anode and IrO_(2)+Pt/C as the cathode.The effects of different discharging/charging current densities and electrolytes on the battery performance were also studied.Neutral K_(2)SO_(4)electrolyte can effectively suppress the passivation of iron electrode,and the battery showed a good cycling stability during 180 charging/discharging cycles.Compared to the pure nano-iron(NanoFe)battery,the NanoFe@CN battery has a more stable cycling stability either in KOH or NH_(4)Cl+KCl electrolyte.