High energy demand results in comprehensive research of novel materials for energy sources and storage applications. Covalent organic frameworks (COFs) possess appropriate features such as long‐range order, permanent porosity, tunable pore size, and ion diffusion pathways to be competitive electrode materials. Herein, we present a deep electrochemical study of two COF‐aerogels shaped into flexible COF‐electrodes (ECOFs) by a simple compression method to fabricate an electrochemical double‐layer capacitor (EDLC). This energy storage system has considerable interest owing to its high‐power density and long cycle life compared with batteries. Our result confirmed the outstanding behavior of ECOFs as EDLC devices with a capacity retention of almost 100 % after 10 000 charge/discharge cycles and, to our knowledge, the highest areal capacitance (9.55 mF cm⁻²) in aqueous electrolytes at higher scan rates (1000 mV s⁻¹) for COFs. More importantly, the hierarchical porosity observed in the ECOFs increases ion transport, which permits a fast interface polarization (low τ₀ values). The complete sheds light on using ECOFs as novel electrode material to fabricate EDLC devices.

High energy demand results in comprehensive research of novel materials for energy sources and storage applications. Covalent organic frameworks (COFs) possess appropriate features such as long‐range order, permanent porosity, tunable pore size, and ion diffusion pathways to be competitive electrode materials. Herein, we present a deep electrochemical study of two COF‐aerogels shaped into flexible COF‐electrodes (ECOFs) by a simple compression method to fabricate an electrochemical double‐layer capacitor (EDLC). This energy storage system has considerable interest owing to its high‐power density and long cycle life compared with batteries. Our result confirmed the outstanding behavior of ECOFs as EDLC devices with a capacity retention of almost 100 % after 10 000 charge/discharge cycles and, to our knowledge, the highest areal capacitance (9.55 mF cm⁻²) in aqueous electrolytes at higher scan rates (1000 mV s⁻¹) for COFs. More importantly, the hierarchical porosity observed in the ECOFs increases ion transport, which permits a fast interface polarization (low τ₀ values). The complete sheds light on using ECOFs as novel electrode material to fabricate EDLC devices.

The exfoliation of tridimensional crystal structures has recently been considered a new source of bidimensional materials. The new approach offers the possibility of dramatically enlarging the library of bidimensional materials, but the number of nanolayers produced so far is still limited. Here, we report for the first time the use of a new type of material, α-germanium nanolayers (2D α-Ge). The 2D α-Ge is obtained by exfoliating crystals of α-germanium in a simple one-step procedure assisted by wet ball-milling (gram-scale fabrication). The α-germanium nanolayers have been tested as anode material for high-performance LIBs. The results show excellent performance in semi-cell configuration with a high specific capacity of 1630 mAh g⁻¹ for mass loading of 1 mg cm⁻² at 0.1 C. The semi-cell was characterized by a constant current rate of 0.5 C during 400 cycles and different scan rates (0.1 C, 0.5 C, and 1 C). Interestingly, the structural characterization, including Raman spectroscopy, XRPD, and XPS, concludes that 2D α-Ge largely retains its crystallinity after continuous cycling. These results can be used to potentially apply these novel 2D germanium nanolayers to high-performance Li-ion batteries.

Rapidly escalating energy demands have spurred a relentless quest for innovative materials and methodologies in energy storage technologies. Covalent organic frameworks (COFs) have emerged as promising candidates for energy storage applications owing to their customizable structure and inherent properties, including enduring porosity and expansive surface area. In this study, we introduce imine-based COF aerogels fashioned into flexible COF electrodes, employing redox electrolytes based on hydroquinone (HQ) dissolved in H₂SO₄ aqueous solution and 0.25 M TBAPF₆ at concentration in acetonitrile. This strategic selection of electrolytes aims to augment capacitance and energy density when compared to non-redox electrolytes. Remarkably, our COF electrodes exhibit an outstanding areal capacitance of 843 mF cm⁻² when utilizing HQ with 0.10 M H₂SO₄, operating at 1.3 mA cm⁻², while maintaining approximately 100% capacity retention after 10,000 cycles. Notably, the capacitance of the 0.38 M HQ + 0.10 M H₂SO₄ is eight times greater than that achieved with organic electrolytes (111 mF cm⁻²).