Although the closed pore structure plays a key role in contributing low-voltage plateau capacity of hard carbon anode for sodium-ion batteries, the formation mechanism of closed pores is still under debate. Here, we employ waste wood-derived hard carbon as a template to systematically establish the formation mechanisms of closed pores and their effect on sodium storage performance. We find that the high crystallinity cellulose in nature wood decomposes to long-range carbon layers as the wall of closed pore, and the amorphous component can hinder the graphitization of carbon layer and induce the crispation of long-range carbon layers. The optimized sample demonstrates a high reversible capacity of 430 mAh g⁻¹ at 20 mA g⁻¹ (plateau capacity of 293 mAh g⁻¹ for the second cycle), as well as good rate and stable cycling performances (85.4% after 400 cycles at 500 mA g⁻¹). Deep insights into the closed pore formation will greatly forward the rational design of hard carbon anode with high capacity.

Aqueous zinc‐ion batteries (ZIBs) have been intensively investigated as potential energy storage devices on account of their low cost, environmental benignity, and intrinsically safe merits. With the exploitation of high‐performance cathode materials, electrolyte systems, and in‐depth mechanism investigation, the electrochemical performances of ZIBs have been greatly enhanced. However, there are still some challenges that need to be overcome before its commercialization. Among them, the obstinate dendrites, corrosion, and hydrogen evolution reaction (HER) on Zn anodes are critical issues that severely limit the practical applications of ZIBs. To address these issues, various strategies have been proposed, and tremendous progress has been achieved in the past few years. In this article, we analyze the origins and effects of the dendrites, corrosion, and HER on Zn anodes in neutral and mildly acid aqueous solutions at first. And then, a scientific understanding of the fundamental design principles and strategies to suppress these problems are emphasized. Apart from these, this article also puts forward some requirements for the practical applications of Zn anodes as well as several cost‐effective‐modifying strategies. Finally, perspectives on the future development of Zn anodes in aqueous solutions are also briefly anticipated. This article provides pertinent insights into the challenges on anodes for the development of high‐performance ZIBs, which will greatly contribute to their practical applications.

Severe zinc dendrite growth is a formidable challenge in aqueous zinc-ion batteries during repeated cycles because of the uneven distribution of electric fields on a post-stripping zinc anode. Herein, we demonstrate a totally new nucleation mechanism by introducing cations with high valence (Ce³⁺ and La³⁺) into the electrolyte to homogenize electric fields and regulate the zinc deposition behavior. Intriguingly, a detailed evolution investigation of surface morphology discloses that zinc nucleation shifts to progressive nucleation via the preferential adsorption of cation additives from instantaneous nucleation in the addtive-free electrolyte, thereby resulting in the stable zinc stripping/plating behavior. A symmetric cell with 0.01 M Ce₂(SO₄)₃ can be cycled at 5 A g⁻¹ with a lower voltage hysteresis of 83.3 mV for more than 700 h, which is remarkably longer than that of the pristine one (282 h). A higher capacity retention of Zn//NaV₃O₈·1.5H₂O cell (87.0%) after 250 cycles at 5 A g⁻¹ is also achieved in comparison with that in addtive-free electrolyte (68.1%). This work provides new and deep insights into the effects of cation adsorption on zinc nucleation.

This review provides a specialized summary of Na ₃ V ₂ (PO ₄ ) ₂ F ₃ cathodes for the first time, including an in-depth discussion of fabrication methods, modification strategies and applications.