We report a clean and easy way to tackle the challenges of large-scale applications of silicon (Si) anodes for lithium-ion batteries. Using an aqueous solution of water-soluble polymer carboxymethyl chitosan and nanosilicon as a precursor, multisize three-dimensional (3D) microspheres as a silicon anode material is fabricated by one-step spray-drying. The effective functional groups, viscoelasticity, and hydrophilicity of polymers are retained, which can prevent the agglomeration of nanoparticles, enhance the internal binding force of the secondary particles, buffer volume expansion, promote the formation of a stable solid electrolyte interface (SEI) film, and maintain electrode integrity. Accordingly, when the mass ratio of Si/polymer reaches 4:1, the compound exhibits a reversible capacity of 1484 mAh g–1 and 75% capacity retention after 100 cycles. Silicon and polymer can be combined effectively via spray-drying, so that the electrode has good cycle stability (930 mAh g–1 after 300 cycles at 1 A g–1), excellent rate performance (871 mAh g–1 at 4 A g–1), and high initial Coulombic efficiency (80%).

A dual‐shell structure Si@SiOx@graphite/graphene (SGGr) is prepared by large‐scale spray‐drying. In this composite, Si nanoparticles act as the core, SiOx and graphite/graphene serve as the shell. Transmission electron microscopy (TEM) studies show that Si nanoparticles are coated with a 1–2 nm SiOx layer and embedded into the sheets of graphite/graphene. Amorphous SiOx and graphite/graphene as the production layer can prevent Si directly connecting with the electrolyte and improve the entire structural stability. In addition, nitrogen adsorption–desorption measurements indicate that the prepared SGGr has a higher Brunauer–Emmett–Teller (BET) surface area (48.4 m2 g−1) than pure Si (36.2 m2 g−1) due to the existence of mesopores and macropores, which can shorten the lithium‐ion transport pathway and provide enough void space for accommodating the volume expansion. The prepared SGGr exhibits a high reversible specific capacity of 1089.3 mAh g−1 after 400 cycles (0.16% decay per cycle), indicating that SGGr has the great potential for industrial application for lithium‐ion batteries.

No abstract

No abstract

No abstract

Silicon anodes are considered to have great prospects for use in batteries; however, many of their defects still need to be improved. The preparation of hybrid materials based on porous carbon is one of the effective ways to alleviate the adverse impact resulting from the volume change and the inferior electronic conductivity of a silicon electrode. Herein, a chain-like carbon cluster structure is prepared, in which MOF-derived porous carbon acts as a shell structure to integrally encapsulate Si nanoparticles, and CNTs play a role in connecting carbon shells. Based on the exclusive structure, the carbon shell can accommodate the volume expansion more effectively, and CNTs can improve the overall stability and conductivity. The resulting composite reveals excellent rate capacity and enhanced cycling stability; in particular, a capacity of 732 mA•h•g −1 at 2 A•g −1 is achieved with a reservation rate of 72.3% after cycling 100 times at 1 A•g −1 .

Peaking carbon dioxide emissions and achieving carbon neutrality is a major strategic decision taken by China and it brings significant pressure and challenges to the transport sector. Peaking carbon emissions is an important direction for the highquality development and green transformation of the transport sector. This study analyzes the status quo of green development and carbon emission in China's transport sector and identifies the challenges for achieving the carbon peak and carbon neutrality goals in the transport sector. The overall idea is to peak carbon emissions actively and steadily by implementing categorized policies, combining short-and long-term goals, controlling carbon emission increment, and adjusting the current emission structure. An overall path for carbon reduction in the transport sector at different stages is proposed. Furthermore, we summarize several key measures

No abstract