Sufficient Utilization of Zirconium Ions to Improve the Structure and Surface properties of Nickel‐Rich Cathode Materials for Lithium‐Ion Batteries

Abstract

We doped Zr ions in the outer layer of Ni Co Mn (OH) by coprecipitation. The distribution of Zr in the final cathode materials showed a gradient distribution because of ion migration during the thermal treatment. The doped layer was confirmed by using various analysis methods (energy-dispersive X-ray spectroscopy, XRD, X-ray photoelectron spectroscopy, and TEM), which implies that Zr can not only occupy both the transition metal slabs and Li slabs but also form a Li ZrO layer on the surface as a highly ion-conductive layer. The doped Zr in the transition metal slabs can stabilize the crystal structure because of the strong Zr-O bond energy, and the doped Zr in the Li slabs can act as pillar ions to improve the structural stability and reduce cation mixing. The gradient doping can take advantage of the "pillar effect" and restrain the "blocking effect" of the pillar ions, which reduces irreversible capacity loss and improves the cycling and rate performance of the Ni-rich cathode materials. The capacity retention of the modified sample reached 83.2 % after 200 cycles at 1C (200 mA g ) at 2.8-4.5 V, and the discharge capacity was up to 164.7 mAh g at 10C. This effective strategy can improve the structure stability of the cathode material while reducing the amount of non-electrochemical active dopant because of the gradient distribution of the dopant. In addition, the highly ion-conductive layer of Li ZrO on the surface can improve the rate performance of the cathode.

Use of Ce to Reinforce the Interface of Ni‐Rich LiNi0.8Co0.1Mn0.1O2 Cathode Materials for Lithium‐Ion Batteries under High Operating Voltage

“…[1][2][3] Rechargeable batteries, as one type of electrical energy storaged evice, can be applied not only for small devicess uch as laptopsa nd smartphones, but also for larges ystems, such as national electric grids, and spacecrafta nd transportation applications,s uch as electric vehicles (EVs). [1][2][3] Rechargeable batteries, as one type of electrical energy storaged evice, can be applied not only for small devicess uch as laptopsa nd smartphones, but also for larges ystems, such as national electric grids, and spacecrafta nd transportation applications,s uch as electric vehicles (EVs).…”

New Insight into the Role of Mn Doping on the Bulk Structure Stability and Interfacial Stability of Ni‐Rich Layered Oxide

“…The obvious separations between the neighboring peaks of (006)/(102) and (108)/(110) show that all the samples have a characteristic highly crystallized layered structure. [28] For the modified samples, it can be observed that the position of (003) peak shifts to a lower angle, which means the expansion of the c axis. The full spectrum fitting with GSAS has been performed to gain the quantitative data of the lattice parameters.…”

“…Observed Bragg diffraction peaks could be indexed to a well‐defined α‐NaFeO 2 ‐type layered structure (R‐3m space group). The obvious separations between the neighboring peaks of (006)/(102) and (108)/(110) show that all the samples have a characteristic highly crystallized layered structure . For the modified samples, it can be observed that the position of (003) peak shifts to a lower angle, which means the expansion of the c axis.…”

The Effects of Trace Yb Doping on the Electrochemical Performance of Li‐Rich Layered Oxides

“…To gain am ore accurate understanding of the doping of Yb ions, Rietveld refinement was performed. [13] The pristine Yb00d id not contain Yb ions, whereas the doped Yb03 displayed Yb ions at Ms ites with an occupancy of 0.27 %. The wRp obtained by the X-ray powder diffraction is about 10%, which is mainly attributed to the influence of the background height.…”