Surface coating by mechanofusion modulates bulk charging pathways and battery performance of Ni-rich layered cathodes

Abstract

Ni-rich layered oxides as high-capacity battery cathodes suffer from degradation at high voltages. We utilize a dry surface modification method, mechanofusion (MF), to achieve enhanced battery stability. The simplicity, high yield, and flexibility make it cost-effective and highly attractive for processing at the industrial scale. The underlying mechanisms responsible for performance improvement are unveiled by a systematic study combining multiple probes, e.g., 3D nano-tomography, spectroscopic imaging, in situ synchrotron diffraction, and finite element analysis (FEA). MF affects the bulk crystallography by introducing partially disordered structure, microstrain, and local lattice variation. Furthermore, the crack initiation and propagation pattern during delithiation are regulated and the overall mechanical fracture is reduced after such surface coating. We validate that MF can alter the bulk charging pathways. Such a synergic effect between surface modification and bulk charge distribution is fundamentally important for designing next-generation battery cathode materials.

Interfacial degradation of the NMC/Li6PS5Cl composite cathode in all-solid-state batteries

“…S5 and S6 †) shows that chemical delithiation introduces slight internal cracks, consistent with our previous study of a similar NMC532 material. 41 To investigate the chemical compatibility between NMC532 and LPSC, aged composite samples were analyzed using Raman spectra and X-ray photoelectron spectroscopy (XPS). The spherical morphology of NMC532 is well maintained aer the chemical delithiation (Fig.…”

“…S5 and S6†) shows that chemical delithiation introduces slight internal cracks, consistent with our previous study of a similar NMC532 material. 41…”

Quantifying the Growth and Evolution of Particle Cracking in Mo2C Anode with Different Cycles Using Soft X-ray Imaging

“…Lithium-ion batteries (LIBs) have become indispensable in the realm of consumer electronics, primarily due to their high energy density and long cycle life. , Among the key components of LIBs, the active particles present in the electrodes play a pivotal role in determining battery performance . However, during cell operation, these active particles are subject to undesired chemical–mechanical processes . Crack formation is a prominent mechanism for performance degradation of advanced electrode materials in recent years, − such as nickel-rich oxide cathode, , silicon anode, etc.…”

“…For these advanced materials, whether intergranular cracks or intragranular cracks, the key to cracking is localized inhomogeneous stress . The presence of cracks leads to an increase of solid–liquid interfacial area, exacerbating side reactions and resulting in heightened resistance. ,, Consequently, the growth and evolution of cracking of the particles are intensified, further contributing to the deterioration of cell performance. Hence, comprehending the mechanical properties of battery electrodes with cycling holds paramount importance in optimizing battery materials for enhanced performance.…”

“…3 However, during cell operation, these active particles are subject to undesired chemical−mechanical processes. 4 Crack formation is a prominent mechanism for performance degradation of advanced electrode materials in recent years, 5−7 such as nickel-rich oxide cathode, 8,9 silicon anode, 10 etc. For these advanced materials, whether intergranular cracks or intragranular cracks, the key to cracking is localized inhomogeneous stress.…”