Avtar Singh

• Doctor of Philosophy
• National Renewable Energy Laboratory

Evolution of complex fracture patterns during electrochemical cycling for the polycrystalline particulate cathode of lithium-ion batteries is found to be a primary reason towards capacity fading. Such fracture of a particles involves inter- and intra-granular crack propagation and often with its debonding from the binder. Till date, a comprehensive...

Staggered structures have materialized to be an exquisite configuration possessing stiffness, strength and toughness, simultaneously. Various biocomposites such as nacre, teeth and bone display aforesaid properties consisting of hard phase in the form of platelets embedded in soft matrix. Platelet fracture, matrix fracture, and platelet-matrix inte...

Composite possesses wide spectrum of mechanical responses along with remarkable fracture strength and toughness. Such properties evolve due to combination of different failure mechanisms across multiple phases. Understanding the contribution of these mechanisms on overall behavior is necessary to fabricate the composite with desired fracture proper...

A thermodynamically consistent multi-physics framework has been developed to understand the chemo-mechanical interplay towards fracture behavior of polycrystalline microstructure along with the current collector. Adopting non-equilibrium thermodynamics, and considering bulk and interfaces as separate systems, the coupled governing equations are der...

Next generation lithium-ion batteries (LIBs) cathodes are composed of polycrystalline microstructures where spatial heterogeneity such as grain size is often comparable to the geometric dimension of the cathodes. Incorporating the influence of the aforementioned heterogeneity in a chemo-mechanical continuum description is necessary to address the d...

Next-generation rechargeable lithium-ion battery anodes must have high energy densities, low costs, and excellent cycle and calendar lifetimes to replace graphite as the incumbent chemistry. Silicon is well positioned to meet these requirements but face two obstacles before reaching commercialization: silicon's large volume expansion during charge...

Interest in all solid-state batteries has been rising due to their potentially safe operation across a wider temperature range and absence of flammable organic solvents. Solid electrolytes are thermally stable up to very high temperatures but their abuse tolerance towards mechanical failure has been debated[1]. It has been reported that thermal run...

Silicon’s potential as a lithium-ion battery (LIB) anode is hindered by the reactivity of the lithium silicide (LixSi) interface. This study introduces an innovative approach by alloying silicon with boron, creating boron/silicon (BSi) nanoparticles synthesized via plasma-enhanced chemical vapor deposition. These nanoparticles exhibit altered elect...

Models exploring electrochemistry-mechanics coupling in liquid electrolyte lithium-ion battery anodes have traditionally incorporated stress impact on thermodynamics, bulk diffusive transport, and fracture, while stress-kinetics coupling is more explored in the context of all solid-state batteries. Here, we showcase the existence of strong link bet...

All-solid-state batteries (ASSBs) provide higher energy densities and safer alternatives to Li-ion batteries by incorporating Li-metal anode and inflammable solid electrolytes. To match the increased capacity of metallic anodes, ASSBs require high-energy-density cathode materials such as LiNi x Co y Mn 1-x-y O 2 (also known as NMC cathode) blended...

In the present work, phase field model has been implemented for simulating hydraulic fracturing in porous reservoir which consists of several poorly connected natural fractures. We have used the finite element method (FEM) for solving the poro-elastic deformation and phase field equation, while the finite volume method (FVM) has been considered for...

It is generally believed that silicon-based anodes for Li-ion batteries would benefit from stronger binders, as cyclic volume changes would not disrupt the cohesion of the composite electrode. Here, we put this belief to the proof by testing electrodes containing SiOx particles and an aromatic polyimide binder. We observe that the electrodes can st...

The utilization of silicon anodes in all‐solid‐state lithium batteries provides good prospects for facilitating high energy density. However, the compatibility of sulfide solid‐state electrolytes (SEs) with Si and carbon is often questioned due to potential decomposition. Herein, operando X‐ray absorption near‐edge structure (XANES) spectroscopy, e...

The utilization of silicon (Si) anodes in all-solid-state lithium batteries (ASLBs) provides the potential for high energy density. However, the compatibility of sulfide solid-state electrolytes (SEs) with Si and carbon is often questioned due to potential decomposition. To investigate this, operando X-ray absorption near-edge structure (XANES) spe...

There are abundant electrochemical-mechanical coupled behaviors in lithium-ion battery (LIB) cells on the mesoscale or macroscale level, such as electrode delamination, pore closure, and gas formation. These behaviors are part of the reasons that the excellent performance of LIBs in the lab/material scale fail to transfer to the industrial scale. T...

Tensile properties and fracture behaviors of silicon rich LM6 aluminum alloy were investigated in details for as cast alloy and modified by LM6 powdery-chip capsules. The obtained results showed that 20% modified LM6 cast composite ensured the excellent tensile properties (tensile strength of 203 MPa with 3.8% elongation). An impressive increase in...