Search

Silicon (Si) has garnered significant attention as an anode material for an advanced lithium-ion battery (LIB), but it remains challenging to design high-stability Si-based composites with low structural strain and high electrical conductivity. Here, we present a novel Si–carbon anode material (Si/G@TNS-60) derived from recycled wire-cutting polysilicon waste, featuring a unique structure with an internal anchoring load and an external wrapping of flexible two-dimensional (2D) material. The graphite (G) component serves as a conductive anchor carrier, enhancing electronic conductivity and preventing pulverization and electrical contact loss in Si particles. Additionally, the MXene (TNS) protective layer provides mechanical flexibility, isolates Si from direct contact with the electrolyte to reduce side reactions, improves ion and electron diffusion kinetics, and ensures structural stability. Consequently, the Si/G@TNS-60 electrode delivers improved initial coulombic efficiency (ICE, 78.8%), excellent rate performance with a capacity of 485.3 mAh g–1at 2 C, and sustained durability over 500 cycles at 0.5 C with 83.5% capacity retention. The investigation into the reaction dynamics reveals the hybrid storage mechanism and rapid Li+diffusion coefficient. Furthermore, ex situscanning electron microscopy (SEM) demonstrates a minimal volume change and maintains the integrity of the electrode structure. Impressively, the full cell based on the Si/G@TNS-60 anode prelithiated by chemical solution technology and LiNi1/3Co1/3Mn1/3O2as the cathode shows a raised ICE of 88.5% and maintains excellent cycle stability. This work fundamentally puts forward a facile and effective structural engineering strategy, highlighting the promising application potential of wire-cutting polysilicon waste in advanced LIB technology.

The growing demand for energy storage application has facilitated the development of Li-ion rechargeable batteries (LIBs). As such, there is an urgent need to design electrodes with a high specific energy and long cycle life. The evolution of conventional LIBs cathode materials in past 30 years has arrived at a bottleneck. Fortunately, the finding of the lithium-rich cation disordered rocksalt (DRXs) has largely broadened the element ranges of the promising cathode in the past several years. Compared with the classical cation-ordered oxides, the DRXs display a large charge storage capacity based on both transition metal and oxygen redox capacity. In addition, their wide compositional space and cobalt-free characteristic would greatly reduce production costs in promoting the commercialization process. Herein, we make an overview of the recent progress for DRXs materials, in terms of their compositions and structure, Li diffusion, charge storage mechanisms, and different redox centra-based system. The key challenges to practical application are also discussed. Last but not least, in order to design high-performance DRXs, we outlined perspectives in developing DRXs for the next generation of LIB cathodes.

The photogalvanic effect (PGE) generated under linearly polarized light irradiation has remarkable applications in 2D nanodevices. The PGE of 2D WS2/Mo2CF2van der Waals (vdW) heterostructure can generate photocurrent and high sensitivity to polarized light. However, the PGE has less photogenerated current. On this basis, the photocurrent transport mechanism of PGE under low bias voltage is investigated. The results show that the photocurrent of the photon energy has cos2θ, sin2θand sin2θdependence on the polarization angle θunder the considered external bias voltage. Under a bias voltage of 1.0 V, the maximum photocurrent of 3.7 eV photon energy in the zigzag direction can reach 4.61. Under a bias voltage of 1 V, the maximum photocurrent of 1.8 eV photon energy in the armchair direction can reach 6.71. The maximum photocurrents are in the order of 10−1for both zigzag and armchair directions with 0 V bias. Furthermore, 2D WS2/Mo2CF2vdW heterostructure has a stable and high extinction ratio. These results show that 2D WS2/Mo2CF2vdW heterostructure is a potential candidate material for future optoelectronics in the visible light region. Herein, the photogalvanic effect of 2D WS2/Mo2CF2van der Waals heterostructures under linearly polarized light is studied. The magnitude of photocurrent in the armchair and zigzag directions is affected by the polarization angle. Meanwhile, 2D WS2/Mo2CF2van der Waals heterostructures have high sensitivity to polarized light and a stable extinction ratio.

It is highly important to develop high-performance sulfur cathode to solve low areal sulfur loading, shuttling and sluggish conversion of polysulfides for lithium-sulfur batteries. Herein, a three-dimensional (3D) freestanding framework configured with Co nanoparticles and Co-Nxcodoped carbon nanotubes anchored in a carbon foam is synthesized and investigated as a new type of sulfur host. Such an architecture can serve not only as a conductive carbon networks but also as host scaffold for high sulfur-containing electrodes. The hierarchical porous structures cooperated with high density and dispersion multifunctional Co-Nxspecies can efficiently trap and manipulate catalytic conversion kinetics of polysulfides. Benefiting from above characteristics, the designed cathodes exhibit a high capacity (1259 mA h g−1) at 0.1 C and excellent cycling performance with an ultralow decay of 0.038% per cycle over 500 cycles at a high current density of 3 C. Even with a high sulfur loading (7.0 mg cm−2) and lean electrolyte (E/S = 5 μL mg−1) operation, a high areal capacity of 4.34 mA h cm−2is still achieved after 100 cycles at 0.1 C. This work provides a low-cost route for preparation of freestanding cathode materials toward highly efficient lithium-sulfur batteries.