Two-dimensional MXene with high conductivity has metastable Ti atoms and inert functional groups on the surface, greatly limiting application in surface-related electrocatalytic reactions. A surface-functionalized nitrogen-doped two-dimensional TiO2/Ti3C2T x heterojunction (N-TiO2/Ti3C2T x ) was fabricated theoretically, with high conductivity and optimized electrocatalytic active sites. Based on the conductive substrate of Ti3C2T x , the heterojunction remained metallic and efficiently accelerated the transfer of Li+ and electrons in the electrode. More importantly, the precise regulation of active sites in the N-TiO2/Ti3C2T x heterojunction optimized the adsorption for LiO2 and Li2O2, facilitating the sluggish kinetics with a lowest theoretical overpotential in both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Employed as an electrocatalyst in a Li–oxygen battery (Li–O2 battery), it demonstrated a high specific capacity of 15 298 mAh g–1 and a superior cyclability with more than 200 cycles at 500 mA g–1, as well as the swiftly reduced overpotential. Furthermore, combined with the in situ differential electrochemical mass spectrometry, ex situ Raman spectra, and SEM tests, the N-TiO2/Ti3C2T x heterojunction electrode presented a superior stability and reduced side reaction along with the high performance toward the ORR and OER. It provides an efficient insight for the design of high-performance electrocatalysts for metal–oxygen batteries.
energy, solar and tidal power, have been investigated in recent years. [2] However, these technologies are easily restricted by the natural environment and geographical location, which have a certain uncontrollability and intermittent supply. [3] Therefore, it is imperative to develop environmentally friendly, advanced, and low-cost energy storage devices to enhance the storage of discontinuous energy. [4] The development of battery technology shows considerable advantages in many energy storage technologies. [5] As a renewable energy storage device, rechargeable batteries show broad application prospects in intelligent electronic devices. [6] Presently, various types of rechargeable batteries, such as Ni-MH batteries, [7] leadacid batteries [8] and Li-ion batteries, [9] have made significant progress and broad application due to their advances in energy density and strong environmental compatibility, as well as their price. [10] Nevertheless, the energy density of conventional Li-ion batteries is limited, which still requires significant improvement. [2,11] To overcome this limitation and extend the service time of mobile electronic devices and the electric vehicles, battery chemistry is rapidly developing, and the newly formed battery system, including lithium-sulfur and Li-O 2 batteries, is expected to achieve higher energy density. [12] As shown in Figure 1, rechargeable LOBs have become promising electrochemical energy storage and conversion devices due to their satisfactory theoretical energy density ≈11 400 Wh kg −1 (calculated based on the pure Li), which was comparable to 12 800 Wh kg −1 of the gasoline. [3,13] Even based on Li 2 O 2 calculation, LOBs had a high specific energy density of 3500 Wh kg −1 . The practical energy density of the LOBs was also close to that of the gasoline, with ≈1700 Wh kg −1 . [13b] As an electrode reactant, oxygen can be directly obtained from the air, which is abundant and inexpensive. Therefore, LOBs have broad prospects for application in energy storage and conversion. [14] Although LOBs have been extensively investigated for several decades and continue to make breakthroughs, they still face various challenges (Figure 2), such as the decomposition of electrolytes, growth of lithium dendrites, parasitic reactions, and slow reaction kinetics, which need to be further explored. [14b,15] LOBs mainly consisted of Li metal anodes, electrolytes and oxygen cathodes. In discharge process, Li metal loses The consumption of fossil fuels has contributed to global warming and other problems. It is urgent to exploit progressive, low-cost, and environmentally friendly energy storage devices with super high energy density. Rechargeable lithium oxygen batteries (LOBs) with a high theoretical energy density (≈11400 Wh kg −1 ) are one of the most promising chemical power supplies. MXenes have recently emerged in energy storage and conversion due to their superior conductivity and adjustable structural properties. Here, this paper summarizes the latest research progress in MXene-based ma...
Lithium–sulfur battery, a promising candidate for rechargeable battery, has aroused wide attention since the traits of high theoretical energy density and low cost. Nevertheless, issues of poor conductivity, severe volume change during cycling, and particular deleterious shuttle effects impede the commercialization of lithium–sulfur batteries. Herein, a convenient and scalable method via electrostatic self-assembly and in situ solvothermal strategies is employed to prepare three-dimensional hierarchical nMOF-867/Ti3C2T x . In this advantageous heterostructure, nMOF-867 with rich porosity not only provides the accommodation of sulfur but also enables chemical binding of polysulfides through stable double bonds (Li–N and Zr–S bond), while the distribution of nMOF-867 on the highly conductive Ti3C2T x would promote redox conversion kinetics of adsorbed polysulfides. Furthermore, structurally stable nMOF-867/Ti3C2T x can serve as a buffer to reduce the volume expansion during the charge/discharge process. Hence, nMOF-867/Ti3C2T x , the sulfur host of lithium–sulfur batteries, exhibits a high reversible capacity of 1302 mAh g–1 at 0.2 C and a remarkable rate capability of 581 mAh g–1 at 4 C. Impressively, a high initial capacity of 801 mAh g–1 can be retained at 1 C, with the slight capacity fading rate of 0.054% per cycle over 1000 charge/discharge cycles. This work provides the inspiration to generally fabricate the well-designed MXene-based nanocomposites for lithium–sulfur batteries with good performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.