Simultaneously Dual Modification of Ni‐Rich Layered Oxide Cathode for High‐Energy Lithium‐Ion Batteries

Abstract

A critical challenge in the commercialization of layer-structured Ni-rich materials is the fast capacity drop and voltage fading due to the interfacial instability and bulk structural degradation of the cathodes during battery operation. Herein, with the guidance of theoretical calculations of migration energy difference between La and Ti from the surface to the inside of LiNi 0.8 Co 0.1 Mn 0.1 O 2 , for the first time, Ti-doped and La 4 NiLiO 8 -coated LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathodes are rationally designed and prepared, via a simple and convenient dual-modification strategy of synchronous synthesis and in situ modification. Impressively, the dual modified materials show remarkably improved electrochemical performance and largely suppressed voltage fading, even under exertive operational conditions at elevated temperature and under extended cutoff voltage. Further studies reveal that the nanoscale structural degradation on material surfaces and the appearance of intergranular cracks associated with the inconsistent evolution of structural degradation at the particle level can be effectively suppressed by the synergetic effect of the conductive La 4 NiLiO 8 coating layer and the strong TiO bond. The present work demonstrates that our strategy can simultaneously address the two issues with respect to interfacial instability and bulk structural degradation, and it represents a significant progress in the development of advanced cathode materials for high-performance lithium-ion batteries.

Irreversible Transition from GaO6 Octahedra to GaO4 Tetrahedra for Improved Electrochemical Stability in Ga-Doped Li(Ni0.9Co0.1)O2

“…EIS measurements were also carried out on both materials under pristine and after 100 cycles. As seen, the obtained Nyquist plots of both materials before cycling consist of a semicircle under a high-frequency region and a straight line at low frequency, consistent with most EIS studies on the layered cathodes . Generally, the semicircle corresponds to the charge-transfer resistance between the electrode and electrolyte, while the linear slope is associated with the lithium migration positively .…”

Cobalt‐Free LiNiO2 with a Selenium Coating as a High‐Energy Layered Cathode Material for Lithium‐Ion Batteries

“…A higher Ni 2þ content in layered materials may exacerbate the degree of Li þ /Ni 2þ cation mixing. [44] This indicates that introducing the Se coating layer can reduce the Li þ /Ni 2þ disorder, consistent with the XRD results. The O1s spectrum in Figure 4c includes peaks corresponding to oxygen vacancies (532.5 eV), oxygen impurities (531.7 eV), and lattice oxygen (529.1 eV).…”

An Efficient Synthetic Method to Prepare High-Performance Ni-rich LiNi0.8Co0.1Mn0.1O2 for Lithium-Ion Batteries

“…In Figure e and f, the differential capacity d Q /d V profiles were calculated to evaluate the structural change during cycling with selected profiles shown. Three redox peaks can be observed, corresponding to the phase transitions of hexagonal (H1) to monoclinic (M), M to hexagonal (H2), and H2 to hexagonal (H3) during charge–discharge cycling, , which is similar to the results of the CV measurements (Figure S2). The d Q /d V profiles are different among the first few cycles, and the redox peak position for the H1–M phase transition shifts to a lower potential after the initial charge/discharge process.…”