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Rechargeable Zn–air batteries (ZABs) are considered highly competitive technologies for meeting the energy demands of the next generation, whether for energy storage or portable power. However, their practical application is hindered by critical challenges such as low voltage, CO2 poisoning at the cathode, low power density, and poor charging efficiency Herein, a rechargeable hybrid alkali/acid Zn–air battery (h‐RZAB) that effectively separates the discharge process in an acidic environment from the charging process in an alkaline environment, utilizing oxygen reduction reaction (ORR) and glycerol oxidation reaction (GOR) respectively is reported. Compared to previously reported ZABs, this proof‐of‐concept device demonstrates impressive performance, exhibiting a high power density of 562.7 mW cm−2 and a high operating voltage during discharging. Moreover, the battery requires a significantly reduced charging voltage due to the concurrent utilization of biomass‐derived glycerol, resulting in practical and cost‐effective advantages. The decoupled system offers great flexibility for intermittently generated renewable power sources and presents cost advantages over traditional ZABs. As a result, this technology holds significant promise in opening avenues for the future development of renewable energy‐compatible electrochemical devices. [ABSTRACT FROM AUTHOR]

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]

Alloying‐type antimony (Sb) with high theoretical capacity is a promising anode candidate for both lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). Given the larger radius of Na+ (1.02 Å) than Li+ (0.76 Å), it was generally believed that the Sb anode would experience even worse capacity degradation in SIBs due to more substantial volumetric variations during cycling when compared to LIBs. However, the Sb anode in SIBs unexpectedly exhibited both better electrochemical and structural stability than in LIBs, and the mechanistic reasons that underlie this performance discrepancy remain undiscovered. Here, using substantial in situ transmission electron microscopy, X‐ray diffraction, and Raman techniques complemented by theoretical simulations, we explicitly reveal that compared to the lithiation/delithiation process, sodiation/desodiation process of Sb anode displays a previously unexplored two‐stage alloying/dealloying mechanism with polycrystalline and amorphous phases as the intermediates featuring improved resilience to mechanical damage, contributing to superior cycling stability in SIBs. Additionally, the better mechanical properties and weaker atomic interaction of Na−Sb alloys than Li−Sb alloys favor enabling mitigated mechanical stress, accounting for enhanced structural stability as unveiled by theoretical simulations. Our finding delineates the mechanistic origins of enhanced cycling stability of Sb anode in SIBs with potential implications for other large‐volume‐change electrode materials. [ABSTRACT FROM AUTHOR]

Sodium borohydride (NaBH4) has earned recognition as a promising hydrogen carrier, attributed to its exceptional hydrogen storage capacity, boasting a high theoretical storage capacity of 10.8 wt %. Nonetheless, the utilization of traditional pyrolysis and hydrolysis methods still presents a formidable challenge in achieving controlled hydrogen generation especially under ambient conditions. In this work, we report an innovative electrochemical strategy for production H2 by coupling NaBH4 electrooxidation reaction (BOR) at anode in alkaline media with hydrogen evolution reaction (HER) at cathode in acidic media. To implement this, we have developed a bifunctional electrocatalyst denoted as Pd‐Mo2C@CNTs, wherein Pd nanoparticles are grown in situ on Mo2C embedded within N‐doped carbon nanotubes. This electrocatalyst demonstrates exceptional performance in catalyzing both alkaline BOR and acidic HER. We have developed a hybrid acid/alkali cell, utilizing Pd/Mo2C@CNTs as the anode and cathode electrocatalysts. This configuration showcases remarkable capabilities for self‐sustained, precise, and uninterrupted indirect release of H2 stored in NaBH4, even at high current densities of 100 mA cm−2 with a Faraday efficiency approaching 100 %. Additionally, this electrochemical device exhibits significant promise as a fuel cell, with the ability to deliver a maximum power density of 20 mW cm−2. [ABSTRACT FROM AUTHOR]

The development of high‐performance sodium ion batteries (SIBs) is heavily relied on the exploration of the appropriate electrode material for Na+ storage, which ought to feature merits of high capacity, easy‐to‐handle synthesis, high conductivity, expedite mass transportation, and stable structure upon charging–discharging cycle. Herein, a universal source‐template method is reported to synthesize a variety of transition metal (e.g., V, Sb, W, Zn, Fe, Co, Ni, and Cu) selenides implanting on N doped 3D carbon nanoarchitecture hybrids (MmSen@3D‐CN) with powerful SeC bonding rivet. Benefiting from the superior architecture and potent SeC bonding between Cu2−xSe and N‐doped 3D carbon (3D‐CN), the Cu2−xSe@3D‐CN nanohybrids, as anode of SIBs, show high capacity, high‐rate capability, and long‐cycle durability, which can deliver a reversible capacity of as high as 386 mAh g−1, retain 219 mAh g−1 even at 10 A g−1, and run durably over thousands of charging–discharging cycles. The Cu2−xSe@3D‐CN as anode is also evaluated by developing a full SIB by coupling with the Na3V2(PO4)3 cathode, which can deliver high energy density and show excellent stability, shedding light on its potential in practical application. [ABSTRACT FROM AUTHOR]

The in situ Fenton reaction utilizing H2O2 has gained significant attention due to its effectiveness in the oxidation of persistent organic pollutants. In this study, we have successfully developed an efficient 2-electron oxygen reduction reaction (2e− ORR) electrocatalyst, Mn-PDA/CNT-2, which exhibits a high H2O2 selectivity of up to 96% within the potential range of 0.65 to 0.85 V vs. RHE in a 0.1 M KOH solution. Moreover, particular emphasis is given to the preparation of an air diffusion floating electrode (ADFE) by incorporating Mn-PDA/CNT-2 onto carbon felt (CF), which enables oxygen in the air to self-drive into the solid state interface of ADFE for the 2e− ORR in bioelectrochemical systems (BESs). Remarkably, the self-aeration ADFE in microbial electrolysis cells (MECs) achieves an impressive maximum current efficiency of 93% for H2O2 production, and the cumulative production of H2O2 reaches a significant amount of 325.18 mg L−1 within a 24 hour period. Additionally, an in situ bio-electro-Fenton system is employed for the degradation of Rhodamine B (RhB). The self-aeration ADFE-MECs system with a Hydraulic Retention Time (HRT) of 6 h demonstrate an effective RhB (6.5 M, pH ≈ 11) degradation rate nearly 90%, accompanied by reduced toxicity in the resulting degradation products. [ABSTRACT FROM AUTHOR]