Boosting the cell performance of the SiO_x@C anode material via rational design of a Si‐valence gradient

Abstract

Relieving the stress or strain associated with volume change is highly desirable for high-performance SiO x anodes in terms of stable solid electrolyte interphase (SEI)-film growth. Herein, a Si-valence gradient is optimized in SiO x composites to circumvent the large volume strain accompanied by lithium insertion/extraction. SiO x @C annealed at 850°C has a gentle Si-valence gradient along the radial direction and excellent electrochemical performances, delivering a high capacity of 506.9 mAh g −1 at 1.0 A g −1 with a high Coulombic efficiency of ~99.8% over 400 cycles. Combined with the theoretical prediction, the obtained results indicate that the gentle Si-valence gradient in SiO x @C is useful for suppressing plastic deformation and maintaining the inner connection integrity within the SiO x @C particle. Moreover, a gentle Si-valence gradient is expected to form a stress gradient and affect the distribution of dangling bonds, resulting in local stress relief during the lithiation/delithiation process and enhanced Li-ion kinetic diffusion. Furthermore, the lowest interfacial stress variation ensures a stable SEI film at the interface and consequently increases cycling stability. Therefore, rational design of a Si-valence gradient in SiO x can provide further insights into achieving high-performance SiO x anodes with large-scale production.

Atomic/Molecular Layer-Deposited Laminated Li2O–Lithicone Interfaces Enabling High-Performance Silicon Anodes

“…These inner tiers could dissipate the internal stress during lithiation, while these outer tiers would guarantee the integrity of the anode material during long-term cycling. Such a dual mechanical behavior has also been proved in previous studies on composite electrodes with zincone/TiO 2 coating, polyacrylic acid (PAA)-polyurethane (BFPU) binder, and Si-valence gradient design. ,, …”

“…Such a dual mechanical behavior has also been proved in previous studies on composite electrodes with zincone/TiO 2 coating, polyacrylic acid (PAA)-polyurethane (BFPU) binder, and Sivalence gradient design. 41,61,62 The interface features between silicon and the electrolyte play a crucial role in maintaining the integrity of the silicon composite anodes as well as retaining its reactivity. We further characterize and quantify the SEI products from electrolyte decomposition with and without the presence of the Li 2 O/ Li 2 O−lithicone film.…”

Manipulating Molecular Structure to Trigger Ultrafast and Long‐Life Potassium Storage of Fe0.4Ni0.6S Solid Solution

“…[ 1,2 ] Among numerous potential candidates, likes sodium‐ion batteries (SIBs), [ 3,4 ] aluminum‐ion batteries (AIBs), [ 5,6 ] and zinc‐ion batteries (ZIBs), [ 7–9 ] potassium‐ion batteries (PIBs) present impressive superiority for large‐scale of energy storage including 1) natural abundance of potassium resources, as well as low cost of production; 2) higher potential energy density and open‐circuit voltage derive from the low redox potential of K/K + (−2.93 V for K/K + vs SHE). [ 10–12 ] Nevertheless, due to the large radius of K‐ions (1.40 Å), the repeated intercalating/extraction processes in active material would cause sluggish diffusion kinetics and extreme volumetric deformation, especially for anode material at a high rate, thus leading to poor structural stability and inferior cycle lifespan. [ 13 ] Therefore, it is significant to explore appropriate anode materials for advanced PIBs.…”

Boosting the overall specific capacity of SiO electrodes for lithium-ion batteries using a multifunctional carbon cloth current collector

“…19 Moreover, it possesses a smaller volume change, higher ionic conductivity, and better cycle performance during the charge and discharge process relative to pure Si. [20][21][22] A commercial W0S1011 hydrophilic carbon cloth (W0CC) was used as the current collector because it can contribute very considerable capacity, which has not been shown by other typical conductive substrates, including other types of carbon clothes. 23 A series of SiO/carbon cloth (SiO@W0CC) composite electrodes were constructed by simply coating the amorphous SiO material on the surface of a commercial hydrophilic carbon cloth (W0S1011).…”