Assembly: A Key Enabler for the Construction of Superior Silicon‐Based Anodes

Abstract

Silicon (Si) is regarded as the most promising anode material for high-energy lithium-ion batteries (LIBs) due to its high theoretical capacity, and low working potential. However, the large volume variation during the continuous lithiation/delithiation processes easily leads to structural damage and serious side reactions. To overcome the resultant rapid specific capacity decay, the nanocrystallization and compound strategies are proposed to construct hierarchically assembled structures with different morphologies and functions, which develop novel energy storage devices at nano/micro scale. The introduction of assembly strategies in the preparation process of silicon-based materials can integrate the advantages of both nanoscale and microstructures, which significantly enhance the comprehensive performance of the prepared silicon-based assemblies. Unfortunately, the summary and understanding of assembly are still lacking. In this review, the understanding of assembly is deepened in terms of driving forces, methods, influencing factors and advantages. The recent research progress of silicon-based assembled anodes and the mechanism of the functional advantages for assembled structures are reviewed from the aspects of spatial confinement, layered construction, fasciculate structure assembly, superparticles, and interconnected assembly strategies. Various feasible strategies for structural assembly and performance improvement are pointed out. Finally, the challenges and integrated improvement strategies for assembled silicon-based anodes are summarized.

New Chemical Synthesis Strategy To Construct a Silicon/Carbon Nanotubes/Carbon-Integrated Composite with Outstanding Lithium Storage Capability

“…To meet the rising demand of electric vehicles for high-energy-density lithium-ion batteries (LIBs), − Si-based materials show great promise as high-capacity anodes as a result of high theoretical capacity (3579 mAh g –1 for Li 15 Si 4 ), environmental friendliness, and low cost. − Nevertheless, the commercial application of a Si-based anode is still limited by its high volume variation and low electronic conductivity (10 –5 –10 –3 S cm –1 ) and ion diffusion coefficient (10 –14 –10 –13 cm 2 s –1 ), which are the main reasons for the poor cycle stability and fast charge performance. − …”

Boosting lithium rocking-chair engineering from the villus cavity and Ni catalytic center of a silicon–carbon anode for high-performance lithium-ion batteries

“…With the booming demand of portable electronics, hybrid and electric vehicles and renewable energy storage systems, Li-ion batteries (LIBs) have become the most attractive electrochemical energy utilization devices due to their high energy and power density, suitable operating voltage, and low selfdischarge. [1][2][3][4][5] However, the limited theoretical specic capacity (372 mA h g −1 ) of graphite, which is commonly used as the anode material, struggles to meet the requirement for the high energy density of next-generation LIBs. [6][7][8][9][10] Endowed with exceptional specic capacity (4200 mA h g −1 ) and low reduction potential (<0.5 V), the silicon anode substance has been developing as a promising substitute for high energy density LIBs.…”

“…18 When considering the superiorities of chemical stability, mechanical strength, excellent electrical/ionic conductivity and permanent skeleton, carbon-based materials have gained much favor in the engineering upgrade of tailoring structures. 2,3,7,[19][20][21] To conquer the above technical issues, integrating the naked silicon substance with a multitudinous carbonaceous matrix, such as commercial carbon nanotubes, graphene, manufactured carbon, or others, to construct felicitous silicon-carbon micro-skeletons (e.g., hierarchical pores and embedding/ doping engineering and core-shell structures) has been a feasible countermeasure. 1,11,[22][23][24][25] As a result, researchers have proposed a number of nanostructured silicon-carbon materials, including silicon/carbon nanotubes, silicon/porous-carbon composites and silicon/graphene, to improve the cycling stability of silicon anodes.…”

“…1,11,[22][23][24][25] As a result, researchers have proposed a number of nanostructured silicon-carbon materials, including silicon/carbon nanotubes, silicon/porous-carbon composites and silicon/graphene, to improve the cycling stability of silicon anodes. 2,9,[26][27][28][29] However, the disadvantages of poor skeleton conductivity, weak carrier diffusion and mismatch between the volume change of silicon and the carbon structure still limit their practical development. 30,31 Due to their oriented and electronic ionic transport paths, one-dimensional (1D) carbon nanobers (CNFs) show substantially excellent kinetic characteristics.…”

Influence of bridge structure manipulation on the electrochemical performance of π-conjugated molecule-bridged silicon quantum dot nanocomposite anode materials for lithium-ion batteries

“…18,19,24–29 In recent years, NP assemblies have come under the spotlight as high-performance anode materials for LIBs owing to their lower interfacial area compared to that of NPs, which can significantly reduce the interparticle resistance and mitigate the risk of side reactions. 25,26 In addition, their high tap density results in thinner electrodes at the same mass loading, which allows shorter electron pathways and increases the volumetric specific capacity of the whole cell. 25,26 Recently, it has been reported that the electrochemical performance of the NP-assembly electrodes can be improved by a robust interconnection of the NPs.…”