Silicate‐Mediated Electrolytic Silicon Nanotube from Silica in Molten Salts

Abstract

Electrochemical preparation/processing of functional silicon from abundant silica is an ideal protocol to promote sustainability of energy sectors. Such an imperative task is challenged by poor electrical conductivity of Si/SiO2 and inadequate mass diffusion of bulk silicon. Herein, a template‐free and one‐step preparation of silicon nanotubes (Si‐NT) from electrochemical reduction of silica in molten salts is reported. An in situ oriented growth of silicate nanorods (NRs) from silica is clarified as the key step to direct a self‐template evolution of Si‐NT from silica. The silicate‐mediated construction of Si‐based NT is versatile and successfully extended to prepare Si‐NT/graphite and TixSiy‐NT. Benefitting from fast longitudinal motorways for fast transport of electrons and ions along/inside NTs, an energy consumption 30% lower than industrial silicon production is achieved. When evaluated as anode of lithium ion battery, the Si‐NT‐based electrodes show outstanding initial Coulombic efficiency and high reversible capacity. The silicate‐mediated construction of Si‐based NT integrates straightforward preparation and intriguing functionality of Si‐based materials, bridging a closed‐loop Si‐based energy infrastructure.

Modulation of Excitonic Confinement of TiO2 in Molten Salts for Overall CO2 Photoreduction†

“…[ 8,14‐15 ] Molten salts are high‐temperature ionic liquids to provide homogeneous reaction medium. [ 16‐18 ] Molten salts have high dissolution of oxygen‐contained and heteroatom‐contained species, accommodating preparation of heteroatom‐contained TiO 2 . [ 19‐20 ] Z‐scheme heterojunction can effectively increase spatially separation efficiency of photogenerated electron‐hole pairs and maxmize redox capacity.…”

A Sustainable Molten Salt Leaching-Electrodeposition Route Toward Converting Rice Husks into Functional Silicon Nanowires and Porous Carbon

“…Silicon nanowires (Si NWs) and porous carbon with excellent physical properties are attracting widespread attention as highly promising functional materials with applications in energy and sustainability. − Especially in power Li-ion batteries, Si NWs are being actively researched and practically promoted . Molten salt electrochemistry enables the facile synthesis of Si nanomaterials and porous carbon materials via an environmentally friendly and cost-effective methodology. − Si NWs can be synthesized by molten salt electrolysis or electrodeposition from silica. , However, for the utilization of RHs biomass, the interaction of silicon and carbon during direct electrolysis of RHs in high-temperature molten salt will inevitably result in the generation of SiC/C or Si/C composite products. ,, Herein, we report a novel molten salt leaching-electrodeposition approach for the facile extraction of Si NWs and the simultaneous production of porous carbon from RH biomass. The dissolution of SiO 2 from RHs in the form of silicates (Ca 2 SiO 4 , etc .)…”

Pure and Metal‐confining Carbon Nanotubes through Electrochemical Reduction of Carbon Dioxide in Ca‐based Molten Salts

“…silicon nanotube. [21] CaO-CaCO 3 transformation plays a critical role in natural carbon cycle, also offering an opportunity to capture CO 2 in more affordable Ca-based molten salts. Thermodynamic data (Figure 1a) show that CaO can function equally with Li 2 O for CO 2 dissolution, which renders CaO a pragmatic alternative to reduce system cost.…”