A high-performance nanoporous Si/Al₂O₃ foam lithium-ion battery anode fabricated by selective chemical etching of the Al–Si alloy and subsequent thermal oxidation

Abstract

Nanostructured micrometer-sized Al-Si particles are synthesized via a facile selective etching process of Al-Si alloy powder. Subsequent thin Al2O3 layers are introduced on the Si foam surface via a selective thermal wet oxidation process of etched Al-Si particles. The resulting Si/Al2O3 foam anodes exhibit outstanding cycling stability (a capacity retention of 78% after 300 cycles at the C/5 rate) and excellent rate capability.

A Novel Approach to Realize Si‐Based Porous Wire‐In‐Tube Nanostructures for High‐Performance Lithium‐Ion Batteries

“…As Figure illustrates, when the C rate is returned step by step from 12 C to C/4 again, the original capacity is largely recovered in each level, revealing the robustness and stability of our structure. These results are comparable to or even better than some of previously reported Si/Al 2 O 3 composite LIB anodes …”

Amphiphilic Graft Copolymers as a Versatile Binder for Various Electrodes of High‐Performance Lithium‐Ion Batteries

“…It is well known that beside the binder, porous Si particles are intriguing structures including large free spaces for expansion during lithiation process to improve their cycling performance. Therefore, we decided to prepare the 3D porous Si particles as anodes through a simple acid etching of Al from Al‐Si alloy powders . X‐ray diffraction (XRD) patterns clearly demonstrated that the acid etching of Al‐Si alloy particles produced pure crystalline Si particles with the absence of Al peaks after etching ( Figure a).…”

Fundamental Understanding of Nanostructured Si Electrodes: Preparation and Characterization

“…Distinctive microstructures from the eutectic phase results in alloy products with mesopores after selective etching . As shown in the left column of Figure a, Al−Si alloys, which are comprised of 87.4 wt% Al and 12.6 wt% Si (i. e., the eutectic point in the Al−Si binary phase diagram), result in a sponge‐like structure without significant deformation either in morphology or crystallinity, even after over 80 wt% of Al is removed from the alloy . Similarly, a Si/SiO 2 composite prepared from a disproportionation of SiO microparticles will have a porous Si structure after selective SiO 2 etching by HF treatment (right column of Figure a) .…”

“… Schematic illustrations for etching methods of nanostructured Si. (a) Al−Si eutectic and disproportionation of SiO . (b) Bulk Si by the metal‐assisted chemical etching (MACE) method.…”