A Passionfruit‐Like Carbon‐Confined Cu₂ZnSnS₄ Anode for Ultralong‐Life Sodium Storage

Abstract

Recent years have witnessed the flourish of lithium-ion batteries (LIBs) in the energy storage markets, ranging from smart vehicles to portable electronic devices. This is because LIBs feature a long cycling lifetime and prominent energy densities. Nevertheless, the limited lithium sources on the earth impose restrictions on the application of LIBs in our daily life. [1] As a next-generation alternative energy storage system to LIBs, sodium-ion batteries (SIBs) have received considerable attention, owing to the natural abundance of Na sources and more importantly their similar energy storage mechanisms to LIBs. [2] However, the ionic radius of a Na + ion (1.02 Å) is larger than that of a Li + ion (0.76 Å), resulting in the huge volume expansion and sluggish electrochemical reaction kinetics during the SIB charge/discharge process. [3] To develop and configure highperformance SIBs, the design of highly stable SIB anode materials is thus of great significance.Recently, various 2D materials (e.g., MXenes, MXene composites, [4] metal-organic frameworks and their derivatives) [5] and 3D ones (e.g., carbon materials) [6] have been explored as the SIB anode candidates. Besides them, transition metal sulfides (TMSs) have been frequently applied, owing to their chemical/ structural stability, low cost, and eco-friendliness. [7] The open architectures of TMSs also provide the facilitations in ionic mobility for the insertion/desertion and diffusion of Na + ions. Such a reaction mechanism in the TMSs has been revealed as a multistep process, including conversion and alloying/dealloying reactions. These reactions guarantee the outstanding theoretical capacities and relatively considerable redox reversibility that is benefited from the weak MS bonds. During the long-term cycling, the conversion reaction in TMSs (MS 2 + 4Na + → M + 2Na 2 S) inevitably leads to severe volume expansion of the TMS anodes. Their drastic construction collapses and thus sharp decays of the capacities occur. It is also known that the alloying-dealloying process at a lower redox potential followed by the conversion reaction always depends upon the alloy formation ability of sodium and metal. [8] However, owing to the poor electrical conductivity, drastic volume changes, and sluggish sodium diffusion kinetics, the limited cycling lifespan and inferior cycling performance of TMSs, these SIBs are still far from what is expected for their scale-up production.The sodium-ion battery (SIB) is one of the new generation of electrochemical energy storage devices, although its life-time needs to be improved. To assemble an SIB with an ultralong life-time, passionfruit-like Cu 2 ZnSnS 4 nanoparticles confined with nitrogen-doped carbon (CZTS@C) are synthesized. As an alternative anode for an SIB, the CZTS@C anode exhibits a reversible capacity of 461 mA h g −1 at a current density of 50 mA g −1 after 140 charge/ discharge cycles and excellent cycling stability (e.g., a capacity of 146 mA h g −1 at 4 A g −1 even after 1000 charge/discharge cycles). Such high pe...

Crosslinking Nanoarchitectonics of Nitrogen‐doped Carbon/MoS2 Nanosheets/Ti3C2Tx MXene Hybrids for Highly Reversible Sodium Storage

“…After fitting and calculation, the capacitive contribution ratios of MoS 2 /Ti 3 C 2 T x @NC at 0.2, 0.4, 0.6, 0.8, and 1.0 mV s −1 , separately, are 92.7, 93.0, 95.5, 96.7, and 97.6 % (Figure 6c). In principle, the high capacitive contribution can be attributed to the rationally designed structure with 2D MoS 2 vertically grown on 2D Ti 3 C 2 T x MXene as well as the simultaneous NC coating, facilitating the redox reactions on the surface of MoS 2 /Ti 3 C 2 T x @NC [43] . Comparatively, the study on the capacitive behaviors for the MoS 2 /Ti 3 C 2 T x and Ti 3 C 2 T x @NC was also conducted, and the results are exhibited in Figure S12 (Supporting Information).…”

Rational design of double-shelled Cu2MoS4@N-doped carbon hierarchical nanoboxes toward fast and stable sodium-ion batteries

“…3a, the diffraction peaks of Cu 2 MoS 4 @NC nanoboxes are highly consistent with those of Cu 2 MoS 4 nanoboxes, but show a weaker peak intensity, probably due to the inuence of carbon coating. 14,33 Furthermore, all the diffraction peaks of the desired products can be indexed to the tetragonal phase Cu 2 MoS 4 (lattice parameters a ¼ 5.4244 Å, b ¼ 5.4244 Å, c ¼ 5.2336 Å, P 42m space group, JCPDS 081-1159). 38,42 No obvious impurity peaks can be detected, indicating the target products with high purity.…”

“…Note that the diffraction peak of carbon cannot be observed in the Cu 2 MoS 4 @NC sample, which is mainly attributed to the low crystallinity and/or content of carbon in the Cu 2 MoS 4 @NC composite. 14,33 Fig. 3b depicts the Raman spectra of Cu 2 MoS 4 and Cu 2 MoS 4 @NC nanoboxes.…”

“…43 Meanwhile, the existence of an external N-doped carbon layer is not only benecial to improving the reaction kinetics, but also to strengthening the structural stability of the obtained nanocomposite. 14,33 The electrochemical performance of the desired materials that served as anodes for SIBs was systematically investigated within a voltage window of 0.1-3.0 V. Fig. 4a shows the cyclic voltammogram (CV) curves of the rst few cycles for the This journal is © The Royal Society of Chemistry 2022 Cu 2 MoS 4 @NC electrode at 0.1 mV s À1 .…”

“…30,31 As an example, Dong and coworkers reported a ZnS-Sb 2 S 3 @C core-double shell polyhedron anode prepared from the ZIF-8 polyhedron (template) and polymeric resorcinol-formaldehyde (carbon source), showing signicantly improved sodium storage with good cycle stability, high coulombic efficiency, and specic capacity. 27 To the best of our knowledge, compared to pure unmodied carbon, heteroatom-doped carbon would be a more desirable conductive substrate to promote the performance of metal suldes due to the following reasons: (i) the stronger affinity of polar doped carbon over nonpolar undoped carbon towards organic electrolytes; 14,32,33 (ii) the enhanced diffusion and storage of sodium ions owing to the high-electronegativity of deciencies readily attracting positive ions; 34,35 (iii) the reinforced structural stability because of the potential chemical/physical interaction between the active sulfur species and doped carbons. 14,36 On account of the considerations above, unfortunately, the ingenious integration of these strategies into one unied system to generate a more desirable composite anode has been rarely reported so far.…”