Characteristics and electrochemical performances of nickel@nano‐silicon/carbon nanofibers composites as anode materials for lithium secondary batteries

Abstract

Si is a next‐generation ideal anode material for Li‐ion batteries (LIBs) because of its high‐theoretical capacity (4200 mAh/g) and natural abundance. However, severe volume expansion and unstable solid electrolyte interface (SEI) film formation during lithiation/delithiation, and poor electron conductivity have significantly restricted the commercial application of Si. In this study, transition metal‐coated Si was synthesized and used as the anode material of LIBs. The transition metal salt of Ni was dissolved in an aqueous solution and used to coat the metal surface of Si nanoparticles. The coating was achieved by dropwise addition of metal solutions into Si dispersions. Thereafter, carbon nanofibers (CNFs) were grown on the transition metal‐coated Si nanoparticles via chemical vapor deposition method. The morphologies, compositions, and crystal quality of transition metal@Si/CNFs composites were characterized by transmission electron microscopy, scanning electron microscopy, x‐ray diffraction, Raman spectroscopy, and thermogravimetric analysis. The electrochemical characteristics of the hybrid anodes were investigated using a coin cell and battery tester. Voltage profile measurements at 0.1 A/g of 0.02 M‐Ni@Si/CNFs composite showed satisfactory initial Coulombic efficiency of 85.6%; 0.01 M‐Ni@Si/CNFs composite exhibited high initial capacity of 1300.9 mAh/g retained to 828.4 mAh/g after 100 cycles, corresponding to 63.7% capacity retention. Even at high current densities, the 0.02 M‐Ni@Si/CNFs composite delivered 342.78 mAh/g of capacity at 5 A/g. This work realizes a Si‐based hybrid anode from Ni‐coated Si catalyst used for direct CNFs synthesis with a stable SEI layer, superior initial Coulombic efficiency with satisfactory cycle and rate performance suitable for commercialized advanced battery applications.

Bubble Wrap-like Carbon-Coated Rattle-Type silica@silicon Nanoparticles as Hybrid Anode Materials for Lithium-Ion Batteries via Surface-Protected Etching

“…The calculated total carbon content for the core shell PDA@SiO 2 @Si sample was approximately 60 wt.%, consistent with the fabrication ratio. Phase III commenced at ~550 • C, marked by sample weight loss due to the oxidation of exposed Si particles that were vulnerable to elevated temperatures [32]. The oxidation reaction persisted into Phase IV, concluding at ~700 • C when all sample components combusted, leaving Si and SiO x components.…”

“…Diverse Si morphologies, including nanoparticles [24,25], nanowires [26], nanotubes [27], nanospheres [28], nanoporous structures [29], and 3D microstructures [30], have been investigated, and various techniques have been developed to enhance the electrochemical performance of Si. Notably, our research group has integrated a range of carbon nanomaterials, such as carbon nanofibers [31,32], carbon nanotubes [33,34], graphene [35,36], and graphene quantum dots [34,37], to augment the electronic conductivity of Si. This approach provides protection against parasitic electrolyte decomposition reactions and mitigates detrimental volume changes.…”

“…Despite the promise of highly functional carbon nanomaterials, challenges such as high-temperature thermal processing [38], expensive precursor materials [39,40], low material yield [41], and complex synthetic routes involving multiple organic reactions and purifications at intermediate steps [42,43] persist as obstacles to electric vehicle (EV) applications. Addressing the urgent need for cost-effective and efficient synthetic routes to produce lithium-ion batteries (LIBs) with advanced features for EVs is crucial, emphasizing the optimization of Si's advantages while addressing issues of severe volume expansion and low conductivity [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”

Revealing Partial Graphitization of Amorphous Carbon in SiO2@C during Magnesiothermic Reduction

“…4200 mAhg –1 ) compared to the conventional graphite anode (372 mAhg –1 ) has received significant attention. Despite this notable advantage, the practical implementation of Si anode has been hindered by substantial volume changes (∼300%) during deep charge/discharge processes, leading to severe mechanical stress and continuous formation of a solid-electrolyte interphase (SEI) layer, as well as intrinsic poor electrical conductivity. − …”