Search

Aqueous zinc (Zn) based batteries show great promise as energy storage devices, cost‐effectiveness, and intrinsic safety. However, the development of Zn‐based batteries faces significant challenges, primarily stemming from poor electrochemical reversibility caused by dendrite growth, hydrogen generation, and byproduct formation on the Zn anode. In this study, valine (Val) is investigated as an electrolyte additive to finely tune the interface microenvironment, resulting in enhanced electrochemical stability of the Zn anode across a wide pH range, marking the first time such an approach has been explored. Val ions preferably adsorb onto the active sites of the Zn anode surface, enabling efficient isolation of water and SO42− from the desolvated shell layer and thus effectively inhibiting dendrite growth. The Zn||Zn symmetric cells are demonstrated with Val electrolyte additives present a remarkable cycling performance of 5400 h. Furthermore, Zn||MnO2 full cells exhibit stable operation for 5000 cycles at 3 A g−1. Notably, the Val additive also functions effectively in rechargeable alkaline cells, enabling the alkaline symmetric cells and Zn||Ni0.8Co0.1Mn0.1O2 full cells to operate durably across a wide temperature range. This work offers unique insights into electrolyte engineering for aqueous rechargeable batteries, especially in terms of their compatibility with a wide pH range. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides with high theoretical capacity usually suffer from poor intrinsic electronic conductivity and drastic volumetric change upon cycling, degrading their attractiveness for electrochemical high‐power and long‐term applications. Herein, a high‐efficiency and extensible synthetic strategy for in situ encapsulating nanostructured SnSe0.5S0.5 into N‐doped graphene (SnSe0.5S0.5 @ NG) by robust interfacial CSeSn bonds with formation of 3D porous network nanohybrids, is reported. Systematic electrochemical studies indicate that interface and structure engineering on SnSe0.5S0.5, including defects implantation, chemical bonding interaction, and nanospace confinement design, endow it with robust structural stability, ultrafast Na+ storage kinetics, and highly reversible redox reaction. In addition, the introduction of foreign Se ligand not only facilitates the transport of electrons/ions by enhancing the conductivity and decreasing the diffusion energy barrier but also generates more reactivity sites, as demonstrated by density functional theory calculations. By virtue of these superiorities, the SnSe0.5S0.5 @ NG exhibits superior sodium storage performance with high‐rate capability and long durability over 2000 cycles at 2 A g−1. Impressively, the full battery, when coupling SnSe0.5S0.5 @ NG anode with Na3V2(PO4)3/C cathode, can deliver high energy density of 213 Wh kg−1. This work provides an effective structural engineering strategy to design advanced electrode material with potential application for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Transition metal sulfides are emerging as promising anode materials for sodium‐ion batteries (SIBs) due to their high theoretical capacity and low cost, their practical application yet face critical issues of sluggish kinetics and poor cycling stability. In this study, a reliable approach is introduced to overcome these challenges by fabrication of Se0.75‐Fe1‐xS0.25@SC hollow nanospheres thanks to the enriched robust Fe─S─C, C─S, and C─Se bonding, which greatly benefit for enhancing both reaction kinetics and structural stability. Kinetic study combining with in situ characterization reveals that the incorporation of rich‐Se into FeSx induces the formation of cationic Fe and Se vacancies, leading to abundant sites and optimized path for sodium storage. Density functional theory calculations also demonstrate how Se‐rich engineering weakens carbonaceous polar C─S─Fe bonds and accelerates reaction dynamics. The as‐prepared Se0.75‐Fe1‐xS0.25@SC can deliver a high reversible capacity of 515 mAh g−1 at 2 A g−1 over 1250 cycles and achieve superior rate capability with maintaining capacity of 418 mAh g−1 at 10 A g−1. This work pioneers the concept of vacancy‐rich functionalized nanostructures, offering a new pathway for designing advanced electrode materials for energy storage devices. [ABSTRACT FROM AUTHOR]

• Bifunctional electrocatalyst of Pd decorating P, N-codoped carbon nanostructures. • A hybrid acid/alkali cell for energy-saving and self-powered generation of H 2. • Indirect releasing H 2 stored in hydrazine by an electrochemical strategy. • Efficient, controllable and continuous release high-purity H 2 from H 2 carrier. Liquid-phase hydrogen (H 2) carriers have received widespread attention owing to their convenient and safe storage and transportation of H 2. Among the various liquid-phase H 2 carriers, hydrazine (N 2 H 4) shows promising applications due to its ability to release H 2 in aqueous solutions via the dehydrogenation process with the assistance of suitable catalysts, which yet produces N 2 /H 2 mixture gas and thus require additional high-energy purification process. In this work, we propose a self-powered electrochemical strategy to indirectly release high-purity H 2 stored in N 2 H 4 by developing a hybrid acid/alkali electrochemical cell, which is set up by coupling alkaline anode for N 2 H 4 electrooxidation reaction (HzOR) with acidic cathode for hydrogen evolution reaction (HER), respectively. For this purpose, Pd nanoparticles uniformly decorating P, N-codoped hollow dodecahedron carbon nanostructures (Pd/PNC) is prepared as bifunctional electrocatalyst for both HzOR and HER, which exhibits high electrocatalytic activity and robust stability. Density functional theory (DFT) calculations imply that P, N-codoping substrate of Pd is conductive to optimize adsorption/desorption sites upon electrocatalysis of HzOR and HER by lowing Gibbs free energy and improving activity. The as-assembled hybrid acid/alkali cell is capable of delivering a maximum power density of 18.2 mW cm−2 and can run stably for 120 h, implementing H 2 generation in a voltage or power controllable manner. This work may inspire exploring the way for efficient, energy-saving, and continuous generation of high-purity H 2. [ABSTRACT FROM AUTHOR]