Mechanical and Electrochemical Stability Improvement of SiC-Reinforced Silicon-Based Composite Anode for Li-Ion Batteries

Abstract

Extreme volume changes and concomitant mechanical instabilities (viz., origin and proliferation of cracking) in Si-based anodes are responsible for premature failure in lithium-ion batteries. Thus, it is a crucial hurdle toward the development of high-performance Si-based batteries, especially in the current scenario of electric vehicles. Accordingly, this research demonstrates a significant improvement in the mechanical stainability of Si-based anode material via in situ incorporation of carbide with a specific design, thereby bestowing outstanding stability in the electrochemical performance. At this juncture, we have established a bridge between nanomechanical and electrochemical properties, investigated via nanoindentation and in-operando stress measurements during electrochemical cycling for Si and in situ reinforced Si–SiC composite. Enhancing the hardness (H) of Si–SiC composite to almost twice as well as enhancing the hardness to effective Young’s modulus (E*) ratio (H 3/E*2) of the same to almost thrice than that of Si, helped resist the occurrence of plastic deformation and cracking in significant terms. In-operando study shows the typical stress flattening (cum, anisotropic behavior) in the case of the unreinforced Si electrode, which is a manifestation of plastic flow/cracking. By contrast, monotonous stress profiles and absence of the signature of plastic flow/cracking are observed for the Si–SiC electrode, which is an advantage for long cycle life, as observed here. Overall, this kind of experimental study could establish the nanomechanical to electrochemical tie-up, leading to 82% capacity retention over 650 cycles in a Li-ion full-cell along with the Si–SiC composite anode. The “power cycle” of the Si–SiC composite anode, with a variation of current density from 0.5 to 6.0 A g–1, also reveals excellent stability up to 2500 cycles.

A review of the multiscale mechanics of silicon electrodes in high-capacity lithium-ion batteries

“…Furthermore, ex situ depth-sensing nanoindentation has been widely explored as an effective technique to probe the Young's modulus and hardness properties of lithiated Si [45,48,49,51] due to its capability for small-volume measurement and minimal requirement for sample preparation. The two properties are determined from a load vs. displacement curve resulting from indenting the surface of lithiated Si at the nanometer scale using a sharp diamond tip [53]. To avoid the chemical reaction of lithiated Si with ambient air during nanoindentation, the samples are usually maintained in a mineral oil or inert gas environment during testing.…”

Direct-Contact Prelithiation of Si–C Anode Study as a Function of Time, Pressure, Temperature, and the Cell Ideal Time

“…This phenomenon is further attributed to the slow breakdown of the crystalline silicon structure. It depends on the migration rate of Li-ions into the silicon host and the rate of amorphous Li–Si alloy formation. , The peak current intensity of the first anodic scan is less for PL-0 than for PL-15 and PL-30 cells due to Li-ion transport hindrance during delithiation for PL-0 (Figure f) . This suggests that artificial SEI growth improves the Li-ion migration rate for PL-15 and PL-30 samples.…”

Understanding the Effects of Tetrahedral Site Occupancy by the Zn Dopant in Li-NMCs toward High-Voltage Compositional–Structural–Mechanical Stability via Operando and 3D Atom Probe Tomography Studies

“…A 100 nm-thick Pt film (as the current collector) was pre-deposited on the quartz substrate via DC magnetron sputtering, having a 20 nm-thick Ti film as an intermediate adhesive layer between the Pt and quartz (as shown in Figure S1 in the Supporting Information). The isotropic, stiff, and Li-inert quartz substrate aids the in-plane stress measurements via the substrate curvature methodology; the procedure and mechanistic aspects of which have been detailed in our previous publications. ,− …”