New Covalent Triazine Framework Rich in Nitrogen and Oxygen as a Host Material for Lithium-Sulfur Batteries

Recent developments in covalent Triazine frameworks for Lithium-ion and Lithium-sulfur batteries

The escalating demand for sustainable energy storage solutions has spurred significant research into materials that can efficiently store and convert energy. Among these, Covalent Triazine Frameworks (CTFs) have emerged as a promising class of two-dimensional nanomaterials due to their unique properties which includes permanent porosity, abundant active sites, exceptional stability and structural diversity. This review examines the role of CTFs in enhancing the performance of electrochemical energy storage devices, particularly in LIBs and LSBs as electrode materials. Despite the advantages of CTFs based electrode materials, such as their lightweight nature, design flexibility, and sustainability, they often suffer from low ionic conductivity and durability issues. This review examines recent advancements and design approaches focused on enhancing the electrochemical performance of CTF-based electrodes for lithium-ion (LIBs) and lithium‑sulfur (LSBs) batteries. It also addresses the major challenges that limit the effectiveness of CTFs in energy storage applications and suggests potential strategies for overcoming these obstacles. The primary aim of this review is to offer a thorough and detailed overview of the current state of research on CTFs. By critically analyzing existing work and highlighting future research directions, this review intends to support the advancement of CTF-based technologies in pursuit of more efficient and sustainable energy storage solutions.

Unveiling Covalent Triazine Frameworks for Lithium Metal Anodes: Recent Developments and Prospective Advances

Lithium metal batteries (LMBs) are distinguished by their elevated energy densities which represent themselves as the formidable contenders for the forthcoming generation of energy storage technologies. Nonetheless, their cycling efficiency is hindered owing to unregulated growth of lithium dendrites and unstable solid electrolyte interphase (SEI). This raises serious safety concerns while rendering LMBs unfeasible for real-world implementation. Covalent Triazine Frameworks (CTFs) have emerged as a promising class of 2D nanomaterials due to their unique properties such as high surface area, chemical stability, tailorable properties, porosity and high N-containing groups. These groups serve as an efficient acceptor for Li. Consequently, the problem of lithium dendrite formation is significantly reduced. This review offers an extensive examination of CTF based anode materials utilized to address the challenges associated with lithium dendrites in LMBs. It is outline future prospects and provide recommendations for the design and engineering of lithium metal anodes (LMAs) and architectures that can make LMBs viable for practical use. This review also highlights promising strategies for surmounting challenges to ensure the safety and efficiency of LMBs.

Flower-Shaped Hollow VOOH Spheres Wrapped by Carbon Nanotubes as the Cathode Electrocatalyst Enable Ultrafast and Long-Lasting Li-S Batteries

Lithium-sulfur batteries (LSBs) have been considered promising candidates for next-generation energy storage devices owing to their high energy density, low price, and environment-friendly characteristics. However, their commercialization has been hindered by the "shuttle effect", which occurs during the charge/discharge cycles and leads to poor cycling performance and low coulombic efficiency. Here, we synthesized flower-shaped hollow VOOH spheres on the carbon nanotube (CNT) network, which were used as the multifunctional sulfur host materials for the first time in LSBs. These VOOH spheres can chemically and physically confine polysulfides as well as catalyze their redox conversion; additionally, their hollow structure can effectively accommodate the volume change during cycling. Moreover, the CNTs among spheres can improve the conductivity of the host material and increase the number of active sites for interfacial reactions. Accordingly, when used as a cathode material, VOOH@CNTs/S composites exhibited a large specific discharge capacity of 1414.63 mAh/g at 0.1 C and excellent cycling stability. At a low current density of 0.5 C, VOOH@CNTs/S exhibited a capacity decay of 0.044% per cycle after 100 cycles. Importantly, at an ultrahigh current density of 5 C, a specific capacity as high as 455.09 mAh/g could be still be delivered after 1000 cycles, corresponding to a superior capacity retention of 90.46% and an ultralow capacity decay of 0.009% per cycle. These findings open up a new material for the practical application of LSBs with ultrafast charge/discharge property and long-lasting cyclic stability.