Ether electrolytes for potassium-ion batteries exhibit a broader electrochemical window and greater applicability, yet most of them are high-concentration electrolytes with elevated cost. In this study, we propose the use of a weakly solvating cyclic ether electrolyte with tetrahydropyran (THP) as the solvent. This approach induces the formation of a thin and dense inorganic-rich solid electrolyte interphase (SEI) film, which is accompanied by a decrease in the activation energy of electrode interfacial reactions due to the weak ligand binding of THP with K⁺. Density functional theory (DFT) simulations also corroborate the hypothesis that K⁺ has a lower binding energy with THP. During potassium storage process, the phenomenon of solvent co-intercalation of graphite does not occur, which greatly reduces the destruction of the graphite structure and enables a superior electrochemical performance and enhanced cycling stability at a lower concentration (2 M). At a current density of 0.2 C (55.8 mA·g^–1), the battery can be stably cycled for 800 cycles (approximately 8 months) with a specific capacity of 171.8 mAh·g^–1. This study provides a new ether-based electrolyte for potassium ion batteries and effectively reduces the electrolyte cost, which is expected to inspire further development of energy storage batteries.

Industrially prepared artificial graphite (AG) is attractive for potassium-ion batteries (PIBs), but its rate performance is poor and the production process is energy intensive, so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically important. Herein, a nanostructured graphite composed of multi-walled carbon nanotubes (MWCNTs) and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework (MOF) and carbon source. The high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency (ICE) exceed 80%, and the three-dimensional (3D) conductive network ensures a specific capacity of 234 mAh·g⁻¹ after 1000 cycles at a high current density of 500 mA·g⁻¹. In addition, the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction (XRD) and in situ Raman spectroscopy, and its practicality is also proved by the voltage of the full cells. This work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.

Carbon-based electrodes of potassium-ion batteries are of great research interest ascribed to their low cost and environmentally friendly distinctions. However, traditional carbon materials usually exhibit weak mechanical properties and incomplete crosslinking, resulting in poor stability and electrochemical performance. Herein, we report a new strategy for modifying reduced graphene oxide into a uniform few-layer structure through a sol–gel method combined with acid etching treatment. The obtained chemical cross-linking and mechanically reinforced carbon network constructed by graphene (CNCG) demonstrates excellent electrochemical and mechanical properties. Adopted as a free-standing anode (~ 7 mg·cm⁻²) for potassium ion battery, the as-achieved CNCG delivers a high reversible specific capacity of 317.7 mAh·g⁻¹ at a current density of 50 mA·g⁻¹ and admirable cycle stability (208.4 mAh·g⁻¹ at 50 mA·g⁻¹ after 500 cycles). The highly reversible structural stability and fully cross-linked properties during potassiation are revealed by ex-situ characterization. This work provides new ideas for the synthesis of new carbon materials and the development of high-performance electrodes.

Aqueous rechargeable zinc ion batteries (ARZIBs) have received unprecedented attention owing to the low cost and high-safety merits. However, their further development and application are hindered by the issues of electrodes such as cathode dissolution, zinc anode dendrite, passivation, as well as sluggish reaction kinetics. Designing heterostructure electrodes is a powerful method to improve the electrochemical performance of electrodes by grafting the advantages of functional materials onto the active materials. In this review, various modified heterostructure electrodes with optimized electrochemical performance and wider applications are introduced. Moreover, the synergistic effect between active materials and functional materials are also in-depth analyzed. The specific modification methods are divided into interphase modification (electrode-electrolyte interphase and electrode-current collector interphase) and structure optimization. Finally, the conclusion and future perspective on the optimization mechanism of functional materials, and the cost issue of practical heterostructure electrodes in ARZIBs are also proposed. It is expected that this review can promote the further development of ARZIBs towards practical utility.