Recent Advances in Layered Ti 3 C 2 T x MXene for Electrochemical Energy Storage

194

132

In recent years, the rapidly growing attention on MXenes makes the material a rising star in the 2D materials family. Although most researchers' interests are still focused on the properties of bare MXenes, little attention has been paid to the surface chemistry of MXenes and MXene‐based nanocomposites. To this end, this Review offers a comprehensive discussion on surface modified MXene‐based nanocomposites for energy conversion and storage (ECS) applications. Based on the structure and reaction mechanism, the related synthesis methods toward MXenes are briefly summarized. After the discussion of existing surface modification techniques, the surface modified MXene‐based nanocomposites and their inherent chemical principles are presented. Finally, the application of these surface modified nanocomposites for supercapacitors (SCs), lithium/sodium–ion batteries (LIBs/SIBs), and electrocatalytic water splitting is discussed. The challenges and prospects of MXene‐based nanocomposites for future ECS applications are also presented.

Section: The Structure and Preparation Methods Of Mxenesmentioning

confidence: 99%

Surface Modified MXene‐Based Nanocomposites for Electrochemical Energy Conversion and Storage

Wang

Yao

et al. 2019

194

132

“…Despite these advances, a control over the etching process to prepare low‐dimensional MOFs remains as a challenge, because it lacks intrinsic driving force for anisotropic etching of MOF crystals. For instance, exfoliation of the bulk inorganic materials into nanosheets always benefits from their intrinsic layered structure, but have been impossible in most of MOFs. The paucity in preparation of low‐dimensional MOFs definitely hinders in‐depth study of nanoscale MOFs, given that their properties are highly size‐ and shape‐dependent …”

Section: Introductionmentioning

confidence: 99%

Well‐Defined Cu₂O/Cu₃(BTC)₂ Sponge Architecture as Efficient Phenolics Scavenger: Synchronous Etching and Reduction of MOFs in confined‐pH NH₃⋅H₂O

Jia

Zhuang

et al. 2019

Fabrication of low‐dimensional nano‐MOFs as well as nanoparticles/metal‐organic frameworks (MOFs) hybrids has sparked new scientific interests but remains a challenging task. Taking Cu3(BTC)2 as a proof of concept, it is demonstrated thats NH3⋅H2O solution of a confined pH value can readily shape the bulk Cu3(BTC)2 into nanoscale Cu3(BTC)2, beyond the need to control the crystal growth kinetics of MOFs. Adjusting the pH of NH3⋅H2O within a much small range (10–11) allows fine tuning over the size and shape of nanoscale Cu3(BTC)2. Particularly at pH = 11, NH3⋅H2O exhibits weak reducibility that triggers a reduction of part of Cu3(BTC)2 into Cu2O, while shaping the other into Cu3(BTC)2 nanowires. Benefiting from the coincidence of reduction and etching effects, the newly generated Cu2O dots can in situ anchor onto adjacent Cu3(BTC)2 nanowires at highly dispersive state, forming a well‐defined sponge‐like architecture built of Cu2O dots and nano‐Cu3(BTC)2. The CuOx derived from annealing of the Cu2O dots/nano‐Cu3(BTC)2 hybrid preserves the sophisticated sponge architecture and high porosity, and exhibits promising applications in phenol scavenging, with efficiency outperforming its counterparts and many other Cu‐based catalysts reported in literature. It is anticipated that the findings here pave the way for the rational design of intricate nano‐MOFs in a more efficient way.

“…For instance, graphitic carbon shows unsatisfactory sodium storage because of the improper intercalated compounds and unmatched layer distance . Consequently, it is stringent to explore suitable host anodes with rapid Na + /electron transport path, and compatible stable structure is the key to fulfill the practical application of SIBs …”

Section: Introductionmentioning

confidence: 99%

Synergistical Coupling Interconnected ZnS/SnS₂ Nanoboxes with Polypyrrole‐Derived N/S Dual‐Doped Carbon for Boosting High‐Performance Sodium Storage

Cao

Bao

et al. 2019

126

Metal sulfides possess tremendous potentials owing to their high specific capacity for sodium storage. However, the huge volume expansion, accompanied with structural collapse and unsatisfied electric conductivity upon continuous cycling, always lead to inferior rate capability and severe cycling fading. In this work, binary metal sulfide (ZnS/SnS2) nanoboxes confined in N/S dual‐doped carbon shell (ZSS@NSC) are fabricated through a facile co‐precipitation method involving the wrapping of polypyrrole, and subsequent in situ sulfidation process. Such a well‐designed heterogeneity between ZnS and SnS2 provides rapid Na+ insertion and enhanced charge transport by creating an electric field at the heterointerface. More significantly, the formation of polypyrrole‐derived N/S dual‐doped carbon is synergistically coupled with the ZnS/SnS2 to create a unique and robust architecture, further strengthening the interconnect function at the heterointerface, which improves electric/ion transfer and mitigates the volume variation during the long‐term cycling process. Herein, this as‐prepared ZSS@NSC exhibits satisfied specific capacity, excellent rate property, and superior cyclic stability (a reversible capacity of 456.2 mAh g−1 with excellent capacity retention of 97.2% after 700 stable cycles at ultrahigh rate of 5 A g−1). The boosted Na‐storage properties demonstrate that the optimized strategy of structure‐engineering has a broad prospect to promote energy storage applications.