Fabrication of Si–SiO2@Fe/NC composite from industrial waste AlSiFe powders as high stability anodes for lithium ion batteries

Dramatic Enhancement Enabled by Introducing TiN into Bread-like Porous Si-Carbon Anodes for High-Performance and Safe Lithium Storage

Doping modifications and surface coatings are effective methods to slow volume dilatation and boost the conductivity in silicon (Si) anodes for lithium-ion batteries (LIBs). Herein, using low-cost ferrosilicon from industrial production as the energy storage material, a bread-like nitrogen-doped carbon shell-coated porous Si embedded with the titanium nitride (TiN) nanoparticle composite (PSi/TiN@NC) was synthesized by simple ball milling, etching, and self-assembly growth processes. Remarkably, the porous Si structure formed by etching the FeSi2 phase in ferrosilicon alloys can provide buffer space for significant volume expansion during lithiation. Highly conductive and stable TiN particles can act as stress absorption sites for Si and improve the electronic conductivity of the material. Furthermore, the nitrogen-doped porous carbon shell further helps to sustain the structural stability of the electrode material and boost the migration rate of Li-ions. Benefiting from its unique synergistic effect of components, the PSi/TiN@NC anode exhibits a reversible discharge capacity up to 1324.2 mAh g-1 with a capacity retention rate of 91.5% after 100 cycles at 0.5 A g-1 (vs fourth discharge). Simultaneously, the electrode also delivers good rate performance and a stable discharge capacity of 923.6 mAh g-1 over 300 cycles. This research can offer a potential economic strategy for the development of high-performance and inexpensive Si-based anodes for LIBs.

Engineering amorphous SnO2 nanoparticles integrated into porous N-doped carbon matrix as high-performance anode for lithium-ion batteries

A facile in-situ preparation strategy is proposed to anchor amorphous SnO₂ nanoparticles into the porous N-doped carbon (NC) matrix to fabricate amorphous composite powders (am-SnO₂@p-NC), which feature the hierarchically interconnected and well interlaced porous configurations by employing polyvinylpyrrolidone as the soft template. The morphology regulation of the porous structure is precisely realized by adjusting the content of the template and the relationship between structural evolution and electrochemical performance of composite powders is accurately described to explore the optimal template dosage. The results indicate that the am-SnO₂@p-NC-50 % composite electrode can deliver the improved lithium storage capacity and cycling performance when the content of the template is controlled at 0.500 g, in which the initial discharge specific capacity is about 1557.6 mAh/g and the reversible value retains at 841.5 mAh/g after 100 cycles at 100 mA/g. Meanwhile, the discharge specific capacity of 869.8 mAh/g is exhibited for the am-SnO₂@p-NC-50 % composite electrode after 60 cycles when the current density is recovered from 2000 to 100 mA/g. Moreover, the Li⁺ ions diffusion coefficient up to about 5.5 × 10^-12 cm²/s is calculated from galvanostatic intermittent titration technique tests, which can be partly ascribed to the conductive NC substrate that provides the high electronic conductivity, and partly to the highly porous structure that shortens Li⁺ ions transfer pathways and guarantees the fast reaction kinetics. Therefore, the hierarchically porous engineering of carbon networks to confine amorphous transition metal oxide nanoparticles is of great significance in the development of high-performance anode materials for lithium-ion batteries.

Silicon Cutting Waste Derived Silicon Nanosheets with Adjustable Native SiO2 Shell for Highly-Stable Lithiation/Delithiation

Silicon is an excellent candidate for the next generation of ultra-high performance anode materials, with the rapid iteration of the lithium-ion battery industry. High-quality silicon sources are the cornerstone of the development of silicon anodes, and silicon cutting waste (SCW) is one of them while still faces the problems of poor performance and unclear structure-activity relationship. Herein, a simple, efficient, and inexpensive purification method is implemented to reduce impurities in SCW and expose the morphology of nanosheets therein. Furthermore, HF is used to modulate the abundant native O in SCW after thermodynamic and kinetic considerations, realizing the mechanical support for the internal Si in the form of an amorphous SiO₂ shell. Afterward, SCNS@SiO₂ -2.5 with a 1.0 nm thick SiO₂ shell exhibits a reversible capacity of 1583.3 mAh g^-1 after 200 cycles at 0.8 A g^-1 . Ultimately, the molecular dynamics simulations profoundly reveal that the amorphous SiO₂ shell is transformed into the extremely ductile Li_x SiO_y shell to ditch stress and relieve strain during the lithiation/delithiation process.

Dimethyl trimethylsilyl phosphite as a novel electrolyte additive for high voltage layered lithium cobaltate-based lithium ion batteries

The addition of 0.5 wt.% of DMTMSP to the electrolyte could improve the low-temperature discharge and cycling performances of high voltage layered lithium cobaltate-based lithium ion batteries.

Porous Si/Fe2O3 Dual Network Anode for Lithium-Ion Battery Application

Benefiting from ultra-high theoretical capacity, silicon (Si) is popular for use in energy storage fields as a Li-ion battery anode material because of its high-performance. However, a serious volume variation happens towards Si anodes in the lithiation/delithiation process, triggering the pulverization of Si and a fast decay in its capacity, which greatly limits its commercial application. In our study, a porous Si/Fe2O3 dual network anode was fabricated using the melt-spinning, ball-milling and dealloying method. The anode material shows good electrochemical performance, delivering a reversible capacity of 697.2 mAh g-1 at 200 mA g-1 after 100 cycles. The high Li storage property is ascribed to the rich mesoporous distribution of the dual network structure, which may adapt the volume variation of the material during the lithiation/delithiation process, shorten the Li-ion diffusion distance and improve the electron transport speed. This study offers a new idea for developing natural ferrosilicon ores into the porous Si-based materials and may prompt the development of natural ores in energy storage fields.

Tin and Tin Compound Materials as Anodes in Lithium-Ion and Sodium-Ion Batteries: A Review

Tin and tin compounds are perceived as promising next-generation lithium (sodium)-ion batteries anodes because of their high theoretical capacity, low cost and proper working potentials. However, their practical applications are severely hampered by huge volume changes during Li⁺ (Na⁺) insertion and extraction processes, which could lead to a vast irreversible capacity loss and short cycle life. The significance of morphology design and synergic effects-through combining compatible compounds and/or metals together-on electrochemical properties are analyzed to circumvent these problems. In this review, recent progress and understanding of tin and tin compounds used in lithium (sodium)-ion batteries have been summarized and related approaches to optimize electrochemical performance are also pointed out. Superiorities and intrinsic flaws of the above-mentioned materials that can affect electrochemical performance are discussed, aiming to provide a comprehensive understanding of tin and tin compounds in lithium(sodium)-ion batteries.