No abstract

Iron corrosion causes a great damage to the economy due to the function attenuation of iron‐based devices. However, the corrosion products can be used as active materials for some electrocatalytic reactions, such as oxygen evolution reaction (OER). Herein, the oxygen corrosion on Fe foams (FF) to synthesize effective self‐supporting electrocatalysts for OER, leading to “turning waste into treasure,” is regulated. A dual chloride aqueous system of “NaCl‐NiCl2” is employed to tailor the structures and OER properties of corrosion layers. The corrosion behaviors identify that Cl− anions serve as accelerators for oxygen corrosion, while Ni2+ cations guarantee the uniform growth of corrosion layers owing to the appeared chemical plating. The synergistic effect of “NaCl‐NiCl2” generates one of the highest OER activities that only an overpotential of 212 mV is required to achieve 100 mA cm−2 in 1.0 m KOH solution. The as‐prepared catalyst also exhibits excellent durability over 168 h (one week) at 100 mA cm−2 and promising application for overall water splitting. Specially, a large self‐supporting electrode (9 × 10 cm2) is successfully synthesized via this cost‐effective and easily scale‐up approach. By combining with corrosion science, this work provides a significant stepping stone in exploring high‐performance OER electrocatalysts.

Heteroatom doping is widely recognized as an appealing strategy to break the capacitance limitation of carbonaceous materials toward sodium storage. However, the concrete effects, especially for heteroatomic phase transformation, during the sodium storage reaction remain a confusing topic. Here, a novel hypercrosslinked polymerization approach is demonstrated to fabricate pyrrole/thiophene hypercrosslinked microporous copolymer and further give porous carbonaceous materials with accurately regulated N/S dual doping corresponding to starting feeding ratios. Significantly, the N doping contributes to the conductivity and surface wettability, while the S doping is bridged to build stable active sites, which can be electrochemically converted into mercaptan anions via faraday reaction and further enhancing reversible capacities. Meanwhile, the abundant S doping can also conduce to the expanded interlayer spacing to shorten the ions diffusion distance, thus optimizing the reaction kinetic. As a result, the N0.2S0.8‐micro‐dominant porous carbon delivers the highest reversible capacity of 521 mAh g−1 at 100 mA g−1 and excellent cyclic stability over 2000 cycles at 2000 mA g−1 with a capacity decay of 0.0145 mAh g−1 per cycle. This work is anticipated to provide an in‐depth understanding of capacitance contribution and illuminate the heteroatomic phase transformation during sodium storage reactions for doping carbonaceous anodes.

Network structured NiO sheets served as a mediator for lithium-sulfur battery coupled with a carbon layer on the cathode side in combination prevented the dissolution of polysulfides, enhanced the rate capability and long-term stability.

Halide solid state electrolytes (SSEs) have attracted the attention of researchers as a new family of SSEs due to simple synthesis, high ionic conductivity, and good softness. However, until now, most of the reported works are focused on promotion of ionic conductivity, and little attention is paid to their air stability and degradation mechanism upon exposure. Herein, the degradation evolution of typical halide SSEs upon moisture is investigated in detail. It is found both Li 3 InCl 6 and Li 3 YCl 6 halide SSEs are easy to absorb water and deteriorate, and the air sensitivity is closely related to the contact area with air. In comparison, the water absorption rate of Li 3 InCl 6 is faster than that of Li 3 YCl 6 , while the amount of water absorption of Li 3 YCl 6 is larger than that of Li 3 InCl 6 , due to the higher solubility of InCl 3 compared to YCl 3 . Along with water absorption, Li 3 InCl 6 first forms a crystalline hydrate, then partially decomposes to InCl 3 and LiCl, and InCl 3 further hydrolyzes and produces acid which is corrosive; finally In 2 O 3 impurities are formed. Coating the surface of Li 3 InCl 6 with Al 2 O 3 can effectively improve the air stability. This work can help to understand the degradation mechanism of halide SSEs and provide guidance for the future design of new halide SSEs.