GeO₂ Encapsulated Ge Nanostructure with Enhanced Lithium‐Storage Properties

Abstract

Germanium (Ge)-based nanostructures, especially those with germanium dioxide (GeO 2 ), have drawn great interest for applications in lithium (Li)-ion batteries due to their ultrahigh theoretical Li + storage capability (8.4 Li/Ge). However, GeO 2 in conventional Ge(s)/GeO 2 (c) (where (c) means the core and (s) means the shell) composite anodes with Ge shell outside GeO 2 undergoes an irreversible conversion reaction, which restricts the maximum capacity of such batteries to 1126 mAhg −1 (the equivalent of storing 4.4 Li + ). In this work, a porous GeO 2 (s)/Ge(c) nanostructure with GeO 2 shell outside Ge cores are successfully fabricated utilizing the Kirkendall effect and used as a lithium-ion battery anode, giving a substantially improved capacity of 1333.5 mAhg −1 at a current density of 0.1 Ag −1 after 30 cycles and a stable long-time cycle performance after 100 cycles at a current density of 0.5 A g −1 . The enhanced battery performance is attributed to the improved reversibility of GeO 2 lithiation/delithiation processes catalyzed by Ge in the properly structured porous GeO 2 (s)/Ge(c) nanostructure.

SnO2 as Advanced Anode of Alkali‐Ion Batteries: Inhibiting Sn Coarsening by Crafting Robust Physical Barriers, Void Boundaries, and Heterophase Interfaces for Superior Electrochemical Reaction Reversibility

“…[106] In the following text, we discuss in detail the mechanisms and various implementation approaches of each of the three strategies, i.e., robust physical barrier-stabilized SnO 2 , hierarchical/porous/hollow-structured SnO 2 with stable void boundaries, and SnO 2 -based heterogenous materials with abundant heterophase interfaces. This review serves as a convenient reference for researchers working on SnO 2 -based materials as well as other analogous LIB anode materials (e.g., silicon dioxide (SiO 2 ) [173][174][175] and germanium dioxide (GeO 2 ) [176][177][178] ) with similar lithium storage mechanisms, and provides some insights for the study of SnO 2 as anodes for other alkali metalion batteries (e.g., sodium-ion battery (SIB), [179][180][181][182][183] and potassium-ion battery (KIB) [184][185][186][187] ) with similar working principles.…”

Structural Strategies for Germanium‐Based Anode Materials to Enhance Lithium Storage

“…The raw material often used GeO 2 , GeCl 4 , and GeBr 2 . Yan et al reported fabricating porous GeO 2 (s)/Ge(c) nanostructure with GeO 2 shell outside Ge cores utilizing the Kirkendall effect, which used the NaBH 4 reduced GeO 2 combined annealing GeO 2 precursors in H 2 /Ar (5% H 2 ) atmosphere to synthesize porous Ge(s)/GeO 2 (c) composites. Due to the improved reversibility of GeO 2 lithiation/delithiation processes catalyzed by Ge, porous GeO 2 (s)/Ge(c) nanostructure showed a stable cycle performance.…”

“…Porous GeO 2 (s)/Ge(c) nanostructure was fabricated by utilizing the Kirkendall effect . The porous GeO 2 (s)/Ge(c) nanostructure exhibited a high reversible capacity of 1333.5 mAh g −1 at a current density of 0.1 A g −1 after 30 cycles, and a long stable cycle capacity of 665.3 mAh g −1 at 0.5 A g −1 after 100 cycles.…”

Using nanoconfinement to inhibit the degradation pathways of conversion-metal oxide anodes for highly stable fast-charging Li-ion batteries

“…Many authors have created highly tailored architectures including anchored-materials, 44 shelled-materials (e.g. singleshell, [45][46][47][48] yolk-shell, 49,50 multi-shell [51][52][53] ), and hierarchical frameworks. [54][55][56] For instance, Deng et al 44 have demonstrated that ZnCo 2 O 4 with cobalt-boride (Co-B) anchors can reduce degradation, volume change and phase segregation.…”