Room temperature assisted nickel-coordination polymer (Ni-CP) is obtained by utilizing the slow diffusion method. The formation of Ni-CP has been confirmed by using single-crystal X-ray diffraction (SC-XRD). The Ni-CP established...

Covalent‐organic frameworks (COFs), being a new member of the crystalline porous materials family, have emerged as important materials for energy storage/conversion/generation devices. They possess high surface areas, ordered micro/mesopores, designable structures and an ability to precisely control electro‐active groups in their pores, which broaden their application window. Thanks to their low weight density, long range crystallinity, reticular nature and tunable synthesis approach towards two and three dimensional (2D and 3D) networks, they have been found suitable for a range of challenging electrochemical applications. Our review focuses on the progress made on the design, synthesis and structure of COFs and their composites for various energy applications, such as metal‐ion batteries, supercapacitors, water‐splitting and solar cells. Additionally, attempts have been made to correlate the structural and mechanistic characteristics of COFs with their applications.

Being cognizant of modern electronic devices, the scientists are continuing to investigate renewable green‐energy resources for a decade. Amid different energy harvesting systems, the triboelectric nanogenerators (TENGs) have been found to be the most promising mechanical harvesting technology and have drawn attention to generate electrical energy. Thanks to its instant output power, choice to opt for wide‐ranging materials, low maintenance cost, easy fabrication process and environmentally friendly nature. Due to numerous working modes of TENGs, it is dedicated to desired application at ambient conditions. In this review, an advance correlation of TENGs have been explained based on the variety of nanostructures, including 0D, 1D, 2D, 3D, metal organic frameworks (MOFs), coordination polymers (CPs), covalent organic frameworks (COFs), and perovskite materials. Moreover, an overview of previous and current perspectives of various nanomaterials, synthesis, fabrication and their applications in potential fields have been discussed in detail.

A cadmium-based metal−organic framework (Cd-MOF) is synthesized in a facile manner at ambient temperature by an easy slow diffusion process. The three-dimensional (3D) structure of Cd-MOF is authenticated by single-crystal X-ray diffraction studies and exhibits a cuboid-shaped morphology with an average edge length of ∼1.13 μm. The prepared Cd-MOF was found to be electroactive in nature, which resulted in a specific capacitance of 647 F g −1 at 4 A g −1 by maintaining a retention of ∼78% over 10,000 successive cycles in the absence of any binder. Further, to distinguish the efficiency of Cd-MOF electrodes, different electrolytes (NaOH, KOH, and LiOH) were explored, wherein NaOH revealed a higher capacitive response due to its combined effect of ionic and hydrated ionic radii. To investigate the practical applicability, an asymmetric supercapacitor (ASC) device is fabricated by employing Cd-MOF as the positive electrode and activated carbon (AC) as the negative electrode, enabling it to light a commercial light-emitting diode (LED) bulb (∼1.8 V). The as-fabricated ASC device delivers comparable energy density and power density.

Covalent organic frameworks (COFs), a distinguished class of porous materials exhibiting precise modularity and crystallinity, and two-dimensional (2D) MXenes, a highly conductive, atomic layered transition metal carbides or nitrides or carbonitrides, are the two fascinating classes of advanced materials that have been intensively researched for energy storage recently. Thanks to the high surface area and porosity of COFs and high electrical conductivity coupled with highly redox active surfaces of MXenes, they have shown great potential in the energy storage applications such as batteries and supercapacitors. However, their electrochemical performance is limited by several inherent issues such as the restacking tendency of MXene sheets and low conductivity of COFs, when applied individually. Combining MXenes and COFs into heterostructures and their use as a single electrode helps in overcoming challenges for improving the energy storage capability. The current perspective intends to provide an overview of designing such COF/MXene heterostructures in the context of the energy storage applications. The research gaps that exist in designing COF/MXene heterostructures and the governing factors for improving the energy storage capability have also been highlighted as opportunities.