Mn₅(H₂O)₄(PO₃OH)₂(PO₄)₂ with an open 3D network was prepared and studied as electrode material for electrochemical capacitors. The material exhibits a tunnel structure along the c axis, characterized by a hydrogen bond network formed by water molecules bonded to MnO₆ octahedra and PO₃-OH tetrahedra units, the latter containing an acidic proton. Electrochemical studies were conducted on both alkaline and neutral electrolytes, revealing a profile indicative of a rapid faradaic process coupled with pseudocapacitance and electrochemical double-layer capacitance. This study proposes a mechanism that involves the interaction between the acidic proton in the tunnel structure and OH⁻ ions from the electrolyte, which diffuse through the hydrogen bond network. The material achieved a maximum specific capacitance of 184 Fg⁻¹ at a scan rate of 5 mVs⁻¹, with an areal capacitance of 4600 µFcm⁻² in 3M KOH. This demonstrates its potential as a high-performance electrode for energy storage applications.

A novel synthesis approach for Cu_0.16VOPO₄·2.5H₂O material is reported, consisting of VOPO₄ layers incorporating water molecules and Cu²⁺ ions within the interlayer space. The inclusion of Cu²⁺ ions leads to significant changes in the previously reported electrochemical properties of VOPO₄·2H₂O. Indeed, copper ion insertion leads to a reduced interlayer space, a higher surface area, and, consequently, to a higher specific charge. Moreover, the appearance of new fast faradaic reactions is depicted from the presence of new redox peaks in cyclic voltammograms. The capacity of this material is 93 Cg⁻¹ in 3 M LiOH, 114 Cg⁻¹ in 3 M NaOH, and 126 Cg⁻¹ in 3 M KOH at a scan rate of 5 mVs⁻¹. It was determined that an intercalation process takes place across the entire operational range in all three electrolytes, even at scan rates as high as 500 mVs⁻¹. Additionally, electrochemical impedance spectroscopy (EIS) was used for a more comprehensive understanding of the electrochemical role of the interlayer Cu²⁺ cations. EIS enables us to propose a new mechanism of electron transfer between VOPO₄ layers and Cu²⁺ ion layers, which extends to neighboring layers, thus explaining the fast kinetic of the related faradaic reactions.

Los avances en nanotecnología han acercado la posibilidad de teléfonos celulares más ligeros, con baterías con mayor duración, procesadores rápidos e incluso pantallas flexibles. Esta ciencia, que manipula la materia a escala nanométrica (<100 nm), ha sido clave en la evolución de la industria electrónica y móvil. El presente artículo pretende explorar cómo las innovaciones en nanotecnología han redefinido los dispositivos móviles y su impacto en el futuro de los celulares, destacando tanto sus beneficios como sus limitaciones. Conforme la nanotecnología avanza, surgen nuevas posibilidades que transforman la experiencia digital, que podrían aplicarse a otros campos.

The ZnS-rGO hybrid materials have demonstrated excellent synergy and a significant enhancement in its properties compared to zinc sulfide (ZnS) and reduced graphene oxide (rGO) separately, positioning it as a promising material for electrochemical supercapacitors. In this work, a ZnS–rGO nanostructured hybrid material was synthesized using a simple, one-step hydrothermal method and thoroughly characterized by different microscopy, spectroscopic and electrochemical methods. The analyses confirmed the formation of rGO sheets decorated with quasi-spherical ZnS nanoparticles. The elemental composition was verified by EDS and XPS, confirming the presence of Zn, S, C and O atoms; furthermore, XPS analysis confirmed the presence of C-C bonds as well as oxygen-rich functional groups (C=O, C-O, and COOH). Additionally, the homogeneous dispersion of ZnS on rGO sheets was confirmed by TEM and EDS mapping. Regarding its optical properties, an increase in the intensity and width of the absorption band of ZnS-rGO was observed, this effect was attributed to the synergy resulting from the transfer of photogenerated charge carriers between ZnS and rGO. Electrochemical characterization demonstrated that the ZnS-rGO hybrid material shows higher specific capacitance than ZnS, with the highest value of 160 Fg-1 in 3M LiOH. The deconvolution of cyclic voltammograms reveals ion intercalation-deintercalation process in which alkali cations occupied the tunnels created by the half tetrahedral unoccupied sites of ZnS blende generating an interstitial charge storage. A remarkable stability upon cycling is observed with 100 % capacitance retention after 5,000 charge-discharge cycles. These results position ZnS-rGO nanostructured hybrid material as a promising negative electrode material for high-performance supercapacitor applications and provides new insight into the charge storage mechanism of ZnS–rGO hybrid electrodes, highlighting the combined contribution of capacitive and diffusion-controlled processes enabled by the synergistic interaction between ZnS nanoparticles and rGO sheets.