A composite surface configuration towards improving cycling stability of Li-rich layered oxide materials

Abstract

Li-rich layered oxides are promising positive electrode candidates for next-generation high energy Li-ion batteries. However, they suffer from a severe gas release issue and side reaction induced surface degradation resulting...

Scalable Nitrate Treatment for Constructing Integrated Surface Structures to Mitigate Capacity Fading and Voltage Decay of Li‐Rich Layered Oxides

“…The calculated ratio of peak I/II (LiTMO 2 to Li 2 MnO 3 phase) for the pristine sample is about 1, implying the uniform distribution of the two compositions. There is an additional peak around 660 cm −1 (peak III) existing in Ce‐ and Y‐treated samples which can be assigned to the oxygen cubic‐close‐packed spinel‐like structure ( Fd ‐3 m space group) [21] . This illustrates the metal ions occupy Li sites successfully to form the integrated layer, coinciding with the HAADF‐STEM results.…”

“…There is an additional peak around 660 cm À 1 (peak III) existing in Ce-and Y-treated samples which can be assigned to the oxygen cubic-close-packed spinel-like structure (Fd-3m space group). [21] This illustrates the metal ions occupy Li sites successfully to form the integrated layer, coinciding with the HAADF-STEM results.…”

“…The LiF component is generated from the attack by HF in the organic electrolyte, which virtually reflects the extent of interfacial reaction. [21] The amount of LiF in the pristine sample is 18.9 %, while there is only 15.4 % in the Y-treated sample. This means the Y-treated sample with a surface-integrated layer is believed to undergo the slight interfacial reactions.…”

“…It can be observed that there are two peaks located at 687.4 eV and 684.9 eV, corresponding to the polyvinylidene fluoride (C−F bond) and LiF components. The LiF component is generated from the attack by HF in the organic electrolyte, which virtually reflects the extent of interfacial reaction [21] . The amount of LiF in the pristine sample is 18.9 %, while there is only 15.4 % in the Y‐treated sample.…”

Enhanced stability of vanadium-doped Li1.2Ni0.16Co0.08Mn0.56O2 cathode materials for superior Li-ion batteries

“…As the number of cycles increase, a new reduction peak around 3.1 V appears during the negative sweep, which corresponds to the reduction of Mn 4+ to Mn 3+ and the gradual transformation of the layered phase to the spinel phase. 61 It should be noted that the reduction peak of the V-1% sample (at approximately 3.1 V) changes insignificantly from the first cycle to the third cycle, which proves that a proper amount of V doping can inhibit the conversion of the layered structure to the spinel structure and improve the structural stability of the material. Furthermore, appropriate V doping can reduce the polarization of REDOX, and the smallest potential difference of 0.36 V can be obtained in the V-1% sample.…”