RESUMEN
The fast development of flexible devices has greatly boosted the demands for flexible lithium-ion batteries (LIBs). Accordingly, a broad exploration of flexible electrodes in LIBs is crucial. At present, the major challenge in the flexible electrode for lithium-ion batteries (LIBs) is how to achieve an excellent electrochemical performance (particularly high-energy density) while maintaining superior mechanical flexibility. Herein, flexible silicon/carbon nanotube (Si/CNT) electrode is prepared via a common blade-coating, which is adoptable to large-scale production. The CNT network from monodispersed CNT solution endows the electrode with superior tensile strength and mechanical toughness. The tensile strength of the flexible electrodes is up to 3.75 MPa, and the corresponding strain at break is 43.9%. The flexible electrode delivers an areal capacity of 10.6 mAh cm-2 at 0.06 mA cm-2, which is completely meet the practical requirement (1-3 mAh cm-2). And a high reversible capacity of 5.64 mAh cm-2 can be retained at 0.3 mA cm-2 after 200 cycles. In addition, the pouch cell exhibits a promising cycling stability under the repeated deformation state. Moreover, this work also provides a feasible and scalable method to fabricate flexible electrodes for other wearable energy storage systems.
RESUMEN
Aqueous zinc-ion batteries (ZIBs) have received great attention due to their environmental friendliness and high safety. However, cathode materials with slow diffusion dynamics and dissolution in aqueous electrolytes hindered their further application. To address these issues, in this work, a MnO2-2 cathode doped with 1.12 wt % Ag was prepared, and after 1000 cycles of charge/discharge at 1 A·g-1, the capacity remained at 114 mA·h·g-1 (only 57.7 mA·h·g-1 for pristine MnO2). Cyclic voltammetry (CV), the galvanostatic intermittent titration technique (GITT), the electrochemical quartz crystal microbalance (EQCM) method, and density functional theory (DFT) calculation on pristine δ-MnO2 and MnO2-2 also proved the superior performance of MnO2-2. More investigation disclosed that its superior performance is attributed to the improved diffusion kinetics of the cathode brought by the enriched oxygen vacancy defects due to the formation of Ag-O-Mn bonds. Meanwhile, the kinetic mechanism of the Zn/MnO2-2 cell can be described as a reversible process of the dissolution/precipitation of the ZHS phase and consequent insertion/extraction of Zn2+ and H3O+. Herein, the primary issues of ZIB cathode materials have been addressed and solved to a certain extent. More importantly, such a modification in the design of the advanced manganese-based aqueous ZIB cathode materials can provide further insight and facilitate the development and application of this large-scale energy storage system in the near future.
RESUMEN
As a typical transition metal dichalcogenide (TMD), molybdenum disulphide (MoS2) has become one of the most promising anode materials for lithium-ion batteries (LIBs) due to its desirable electrochemical properties. But the development of commercial MoS2 is limited by the problem of agglomeration. Thus, the production of MoS2 nanosheets with few (<10) layers is highly desired but remains a great challenge. In this work, a facile and scalable approach is developed to prepare large-flake, few-layer (4-8) MoS2 nanosheets with the assistance of ultrasonics. Simultaneously, the as-prepared MoS2 nanosheets and commercial bulk MoS2 were analysed under multiple spectroscopic techniques and a series of electrochemical tests to understand the dependence of electrochemical performance on structural properties. When used as anode materials for LIBs, the obtained MoS2 nanosheets provide a reversible capacity of 716 mA h g-1 at 100 mA g-1 after 285 cycles, and demonstrated an excellent capacity retention rate of up to 80%. Compared with that of commercial MoS2 (14.8%), the capacity retention rate of our MoS2 nanosheets has a significant improvement. This work explored the ability of few-layered MoS2 nanosheets in the field of LIBs while suggesting the commercialization of the MoS2 by an ultrasonicated ball milling exfoliation technique.
RESUMEN
Two-dimensional conductive metal-organic frameworks (2D CMOFs) can be regarded as high-performance electrode substances owing to their rich hierarchical porous architecture and excellent electrical conductivity. However, the sluggish kinetics behavior of electrodes within the bulk structure restricts their advances in energy storage fields. Herein, a series of graphene-based mixed-dimensional composite aerogels are achieved by incorporating the 2D M-tetrahydroxy-1,4-quinone (M-THQ) (M = Cu, Cu/Co, or Cu/Ni) into CNTs@rGO aerogel electrodes using a 3D-printing direct ink writing (DIW) technique. Benefiting from the high capacity of M-THQ and abundant porosity of the 3D-printed microlattice electrodes, an excellent capacitive performance of the M-THQ@CNTs@rGO cathodes is achieved based on the fast electron/ion transport. Furthermore, the 3D-printed lithium-ion hybrid supercapacitor (LIHCs) device assembled with Cu/Co-THQ@CNTs@rGO cathode and C60@VNNWs@rGO anode delivers a remarkable electrochemical performance. More importantly, this work manifests the practicability of printing 2D CMOFs electrodes, which provides a substantial research basis for 3D printing energy storage.
RESUMEN
Si/C microsphere anodes with well-designed structures were successfully synthesized via the polymerization-induced colloid aggregation (PICA) method. The voids and void-holes in the carbon framework provide the direct and elastic buffer space for volume expansion of Si nanoparticles, respectively. This anode exhibits an outstanding structural integrity and enhanced cycling stability.
RESUMEN
The high usage for new energy has been promoting the next-generation energy storage systems (ESS). As promising alternatives to lithium ion batteries (LIBs), sodium ion batteries (SIBs) have caused extensive research interest owing to the high natural Na abundance of 2.4 wt.% (vs. 0.0017 wt.% for Li) in the earth's crust and the low cost of it. The development of high-performance electrode materials has been challenging due to the increase in the feasibility of SIBs technology. In the past years, bimetallic sulfides (BMSs) with high theoretical capacity and outstanding redox reversibility have shown great promise as high performance anode materials for SIBs. Herein, the recent advancements of BMSs as anode for SIBs are reported, and the electrochemical mechanism of these electrodes are systematically investigated. In addition, the current issues, challenges, and perspectives are highlighted to address the extensive understanding of the associated electrochemical process, aiming to provide an insightful outlook for possible directions of anode materials for SIBs.
RESUMEN
Lithium metal is a promising anode material with extremely high theoretical specific capacity (3,860 mA h g-1), low density (0.59 g cm-3), and the lowest negative electrochemical potential of all potential candidates (-3.04 V vs. the standard hydrogen electrode). However, uncontrollable Li dendrite growth leads to a short lifespan and catastrophic safety hazards, which has restricted its practical application for many years. Some effective strategies have been adopted regarding these challenges, including electrolyte modification, introducing a protective layer, nanostructured anodes, and membrane modification. Carbon-based materials have been demonstrated to significantly address the challenge of Li dendrites. In this review, carbon-based materials and their application and challenges in lithium metal anode protection have been discussed in detail. In addition, the applications of lithium anodes protected by carbon-based materials in Li-S batteries and Li-O2 batteries have been summarized.
RESUMEN
The large volume expansion of FeS2 is successfully accommodated via a series of asynchronous redox reactions of dual-crystalline FeS2. Consequently, a durable sodium storage performance with a reversible capacity of 567.7 mA h g-1 is obtained at 0.1 A g-1 after 50 cycles. This novel strategy can also be utilized in other types of electrodes having large volume change upon cycling.
RESUMEN
In this study, mesoporous ZnCo2O4/rGO nanocomposites were favorably synthesized via a simple solvothermal technique. As a prospective anode material for sodium-ion batteries, the resulting ZnCo2O4/rGO-II nanocomposite exhibited superior electrochemical sodium storage performance with predominant specific capacity, favorable cyclability and ascendant rate capability. For example, an outstanding discharge capacity of 210.5 mAh g-1 was delivered at a current density of 200 mA g-1. Notably, the nanocomposite could yield a discharge capacity of 101.7 mAh g-1 at a current density of 1000 mA g-1 after 500 loops, which certifies its superior capacity retention and predominant cycling stability. The boosted performance of the anode materials is due to the mutual synergistic effect resulting from a combination of the mesoporous ZnCo2O4 nanospheres and conducting reduced graphene oxide nanosheets.
