Review on the Experimental Characterization of Fracture in Active Material for Lithium-Ion Batteries

Abstract

Nowadays, lithium-ion batteries are one of the most widespread energy storage systems, being extensively employed in a large variety of applications. A significant effort has been made to develop advanced materials and manufacturing processes with the aim of increasing batteries performance and preserving nominal properties with cycling. Nevertheless, mechanical degradation is still a significant damaging mechanism and the main cause of capacity fade and power loss. Lithium ions are inserted and extracted into the lattice structure of active materials during battery operation, causing the deformation of the crystalline lattice itself. Strain mismatches within the different areas of the active material caused by the inhomogeneous lithium-ions concentration induce mechanical stresses, leading ultimately to fracture, fatigue issues, and performance decay. Therefore, a deep understanding of the fracture mechanics in active materials is needed to meet the rapidly growing demand for next-generation batteries with long-term stability, high safety, excellent performance, and long life cycle. This review aims to analyze the fracture mechanics in the active material microstructure of electrodes due to battery operations from an experimental point of view. The main fracture mechanisms occurring in the common cathode and anode active materials are described, as well as the factors triggering and enhancing fracture. At first, the results obtained by performing microscopy and diffraction analysis in different materials are discussed to provides visual evidence of cracks and their relation with lattice structure. Then, fatigue phenomena due to crack growth as a function of the number of cycles are evaluated to assess the evolution of damage during the life cycle, and the effects of fracture on the battery performance are described. Finally, the literature gaps in the characterization of the fracture behavior of electrode active materials are highlighted to enhance the development of next-generation lithium-ion batteries.

Aging Mechanisms of Lithium-ion Batteries

“…A total volume expansion of 13.2% was observed when the graphite was fully lithiated (5.9% in stage 2 and 7.3% in stage 1). During repeated electrochemical cycles, cracks can develop and propagate in the graphite particles owing to the stresses generated by repeated volume expansion and contraction [42][43][44][45][46]. Rapid charging and discharging processes have been found to accelerate crack formation because of abrupt volume changes [43,45,46].…”

“…During repeated electrochemical cycles, cracks can develop and propagate in the graphite particles owing to the stresses generated by repeated volume expansion and contraction [42][43][44][45][46]. Rapid charging and discharging processes have been found to accelerate crack formation because of abrupt volume changes [43,45,46]. Exposed fresh graphite surfaces are susceptible to SEI formation reactions, contributing to cell degradation through additional Li + consumption and increased impedance [18,46].…”

Accurate Model Parameter Identification to Boost Precise Aging Prediction of Lithium‐Ion Batteries: A Review

“…evaluated in detail the modeling of fracture mechanics for the microstructure of LIB electrodes. [ 19 ]…”

“…Pistorio et al evaluated in detail the modeling of fracture mechanics for the microstructure of LIB electrodes. [19] More importantly, as big data technologies and artificial intelligence (AI) advance in the future, the integration of PBMs and ML algorithms to leverage the strengths of each to enhance battery life prediction is bound to become an increasingly important area of research. Integration strategies involve serial integration of independent models and hybrid PB and ML models.…”

Advantages of a Solid Solution over Biphasic Intercalation for Vanadium-Based Polyanion Cathodes in Na-Ion Batteries

“…The number of possible rate-limiting steps increases with addressing higher technological levels, while the corresponding limitations remain poorly understood and commonly misinterpreted even at the level of a single particle of an MIB material . Polarization effects, which appear at high charge/discharge rates at room temperature and already at low charge/discharge rates at low temperatures, originate from the same sources of kinetic limitations: slow transport of ions in the electrolyte and the pores of composite electrodes with high tortuosity (ohmic polarization and concentration polarization in the porous medium), slow charge transfer at the electrode/electrolyte interface, , which causes the overpotential buildup (translating into continuous solvent oxidation and detrimental Li or Na plating at the carbonaceous anode at high charge rates and/or at low temperatures), polarization due to the slow diffusion/propagation of phase boundaries in the primary particles of the electrode materials, associated with mechanical stresses induced by steep concentration gradients inside the active materials, which lead to fracture, fatigue issues, and performance decay . The degradation mechanisms and patterns under low-temperature conditions , and at high charge/discharge rates , are, however, different, which again requires careful analysis and material-specific solutions to achieve satisfactory performance at extreme limits of LIBs and SIBs operation.…”