Double-Network Gel-Enabled Uniform Incorporation of Metallic Matrices with Silicon Anodes Realizing Enhanced Lithium Storage

Abstract

Silicon–metal (Si–M) binary materials manifest high tap densities and areal capacities and desirable Li-storage behavior benefiting from metallic matrices and thus have been regarded as promising anodic choices in next-generation Li-ion batteries. To fully realize the hybridization merits, the uniform incorporation of metallic components with silicon is a prerequisite, yet it remains a significant challenge via facile and economic routes. Herein we develop an all-inorganic, double-network, gel-enabled methodology for the uniform incorporation of metallic matrices with silicon anodes. Taking Si–Ti binary materials as an example, the simultaneous gelation reaction for both SiO2 and TiO2 gel networks ensures the formation of integrative SiO2–TiO2 double-network gels, guaranteeing the uniform incorporation of metallic titanium with nanoporous silicon framework via a subsequent magnesiothermic coreduction process. Thanks to the unique structural and compositional features, the as-prepared Si–Ti binary framework exhibits a long cycle life (1161 mA h g–1 after 100 cycles at 0.5 A g–1) and a high rate capability (1405 and 1190 mA h g–1 at 1 and 2 A g–1, respectively).

A Facile Strategy to Construct Silver‐Modified, ZnO‐Incorporated and Carbon‐Coated Silicon/Porous‐Carbon Nanofibers with Enhanced Lithium Storage

“…This obtained LIB performance revealed that adding Ag NPs combined with trace ZnO modification can obviously reduce the electrodes' interface polarization, enhance their conductivity, and finally improve their LIB performance. According to the previous reports, metallic components including Ag may act as diffusion barrier to limit the full lithiation of silicon, and the inhibition of its phase transition greatly improves their structural stability and cyclic life. In particular, a comparison between this work and the recently reported excellent Si‐based anodes has been compared in Table S1 in the Supporting Information, indicating the performance for Ag/ZnO‐Si@C‐PCNFs is better than most similar reports on Si/C anodes.…”

Inorganic Gel-Derived Metallic Frameworks Enabling High-Performance Silicon Anodes

“…Moreover, the amorphous nanoparticle, located within the mesopore and attached to the crystalline nanodendrite, can be identified as a silicon fragment by its microarea EDS spectrum with an ultrahigh Si/Sn atomic ratio of 9.8:1 (Figure d). The crystalline/amorphous phase transition of silicon during cycling is further confirmed by Raman spectra, which show a negative shift from 514 cm –1 in uncycled state to 466 cm –1 in delithiated framework (Figure e) …”

“…Similarly to carbon, metallic matrix can promote electron/ion transport and help maintain electrode integrity of silicon anodes. Besides these common merits, metallic components possess their own properties and peculiar electrochemical mechanisms to boost Si-based lithium storage. − Generally, silicon–metal (Si–M) anodes manifest higher tap densities and volumetric energy densities than Si and Si–C ones . Moreover, the concurrent lithium-storage dynamics between active metals (M′ = Ge, Sn, Sb, etc.)…”

“…Up to now, a series of electrochemically active and inactive metals have been integrated with silicon to realize improved overall lithium storage performance benefited from the hybridization merits of metallic matrices. − However, in these Si–M anodes metallic species often exist in the form of zero-dimensional (0D) particles isolated from each other, failing to provide enough free space for silicon volume changes as well as continuous charge transport pathways. − In this regard, structural engineering of metallic matrices, especially adopting 3D interconnected metallic frameworks, is highly desirable to address the intrinsic pulverization and conducting challenges of silicon anodes. Recently, 3D carbonaceous frameworks, including amorphous carbon, , graphene, and conducting polymers (CP), enable encapsulated silicon particles to exhibit prolonged cyclic life and enhanced rate capability toward lithium storage, owing to their structural integrity and stability as well as 3D electron/ion mixed conducting networks.…”

Synthetic Methodologies for Si‐Containing Li‐Storage Electrode Materials

“…Metal and metal oxide as other interface layers to improve the electrochemical performance for Si‐based anode have also been investigated. [ 291 ] Some metals such as Mg, [ 292 ] Al, [ 293 ] Ti, [ 294 ] Fe, [ 295 ] Ni, [ 296 ] Cu, [ 297 ] Zn, [ 298 ] Ge, [ 299 ] Ag, [ 300 ] and alloy [ 301 ] are applied to fabricate Si‐based anode due to their excellent conductivity and ductility. Wu et al designed 3D Sn–Ni alloy frameworks to in situ immobilize the commercial Si particles via the gel‐reduction route to boost lithium‐storage performance of silicon anodes.…”