Constructing Sub 10 nm Scale Interfused TiO₂/SiO_x Bicontinuous Hybrid with Mutual-Stabilizing Effect for Lithium Storage

Abstract

TiO 2 has been considered as a promising intercalation lithium-ion-battery (LIB) anode material owing to its robust cyclability. However, it suffers from low capacity. Herein, we construct a sub 10 nm scale interfused TiO 2 /SiO x hybrid with a bicontinuous structure, in which bridged TiO 2 nanoparticles (over 80 wt %) are densely packed within a wormlike SiO x network, through the simple oxidation of MAX Ti 3 SiC 2 ceramic. State-of-theart in situ microscopy characterization unravels a "mutualstabilizing" effect from the interfused TiO 2 /SiO x hybrid upon lithiation. That is to say, the two interpenetrated active components restrain the volume expansion of each other with the stress being relieved through abundant interfaces. Meanwhile, the stress generated from one phase functioned as the compressive force on the other phase and vice versa, offsetting the overall volume effect and synergistically reinforcing the structure integrity. Benefiting from the "mutual-stabilizing" effect, the TiO 2 /SiO x composite manifests a high and stable specific capacity (∼671 mAh g −1 after 580 cycles at 0.1 A g −1 ) with a low volume expansion of ∼14% even in an extended potential window of 0.01− 3.0 V (vs Li + /Li). The concept of mutual-stabilizing effect, in principle, applies to a wide class of interfused bicontinuous hybrids, providing insight into the design of LIB anode materials with high capacity and longevity.

Converting bulk MoSi2 alloy to a SiOx based anode material through controlled oxidation induced sublimation

“…Thus, constructing SiO x -based composite materials has attracted increasing attention. A variety of materials, such as carbon, [30][31][32][33][34][35][36][37] transition metals, [38][39][40][41] and transition metal oxides [42][43][44][45] have been composited with the SiO x to boost the performance. However, the easy and scalable integration of SiO x and such materials with satisfactory electrochemical performance is usually challenging.…”

Design of SiO x /TiO2@C hierarchical structure for efficient lithium storage

“…Anatase titanium dioxide (TiO 2 ) has quite an inferior volume expansion rate and a stable structure [23]. Meanwhile, the Li x TiO 2 , (0 x 1) generated after lithiation has excellent electrical conductivity and good reversibility, which is ideal for composite materials [24][25][26][27][28][29][30][31]. Xin and co-workers prepared a SiO x @TiO 2 @CNF composite with a doubleconstrained structure by electrospinning and sol-gel methods.…”

“…Yu and co-workers constructed a sub-10 nm scale interfused TiO 2 /SiO x hybrid with a bicontinuous structure by simply oxidizing MAX Ti 3 SiC 2 ceramic. Benefiting from the 'mutual stabilization' effect, the TiO 2 / SiO x composite exhibits a high and stable specific capacity (∼671 mA h g −1 after 580 cycles at 0.1 A g −1 ) with a low volume expansion of ∼14% even in an extended potential window of 0.01−3.0 V (versus Li/Li + ) [33]. However, these preparation techniques are typically pricy and harsh, not suitable for large-scale preparation.…”

A Gradient Composite Structure Enables a Stable Microsized Silicon Suboxide-Based Anode for a High-Performance Lithium-Ion Battery

“…To further investigate the gradient composite structure, three-dimensional (3D) tomography reconstruction is performed. , Sixty-six HAADF-STEM images were collected over 132° in 2° intervals for tomography reconstruction (Figure g and Video S1). A reconstructed model of d-SiO@SiO x /C@C with the physics color mode is shown in Figure h.…”