A dataset of the thioacetmide supported formation of ZrO2 coating on Ni-rich layered structure cathode materials in lithium-ion batteries.

A dataset in this report is regarding a research article “Crucial Role of Thioacetamide for ZrO2 Coating on the Fragile Surface of Ni-rich Layered Cathode in Lithium Ion Batteries” [1]. Thioacetamide (TA) is introduced to form a homogeneous ZrO2-coating in a facile method through washing with Zr(SO4)2 aqueous solution. The presence of the data in this paper indicated the role of TA for surface modification of LiNi0.82Co0.09Mn0.09O2 (NCM82) materials by ZrO2, leading to improve the electrochemical performance of NCM82 Ni-rich cathode materials. These data were proceeded measurement electrochemical properties of cathode electrode on a battery cycler, the surface characteristics of the cathode materials were investigated by SEM, EDS mapping, TEM and XPS. X-ray diffraction (XRD, Rigaku, SmartLab) was used to evaluate the influence of the coating layer on the microstructure of active materials.


Value of the Data
• This research is essentially understanding the role of TA in the surface modification for Nirich cathode materials by ZrO 2 via washing in Zr(SO 4 ) 2 aqueous solution.
• Data in this paper shows a homogeneous ZrO 2 layer formed on the surface of NCM82, leading to enhance the electrochemical performance of Ni-rich cathode materials. • In this work, the TA has been controlling the pH value of the coating solution and supported Zr ions evenly distributed on the surface of Ni-rich cathode materials. • This data provides a simple surface modification method for NCM Ni-rich cathode materials, low cost with ZrO 2 coated layer-based Zr-precursor and can be widely applied for coating technologies of transition metal oxide.

Data description
The data in this work has been derived by fabrication of the ZrO 2 -coated layer by simple washing method. Figs. 1 and 2 show the structure change of host materials due to immersed in the coating solution. Fig. 3 shows the effect of different coating solution on the surface coating properties of the NCM82 cathode materials. Figs. 4 and 5 show the effect of coating solution on the surface morphologies of NCM82 materials, simultaneously description the thickness of ZrO 2 coating layer. Fig. 6 shows the amount of lithium impurities eliminated by coating solution and pH value of the coating solution was controlled by TA. Fig. 7 shows the effect of concentration of TA on the electrochemical performance of the ZrO 2 -coated NCM82 Ni-rich cathode materials.

Experimental design, materials, and methods
The washing process and simultaneously surface coating by the aqueous solution is the simple method, the impurities on the surface of host materials are elimination and immediately Zr-precipitation to establish a solid protective layer for cathode materials. Many chemical and physical parameters influence the overall process outcome. These include material parameter (pH value, Li delithiation, concentration, thickness and lattice parameter), electrochemical process (fading capacity, cycle and capacity). Experiment detail for the fabrication of ZrO 2 -coated layer has been previously presented. The Zr(SO 4 ) 2. • 4H 2 O, TA were dissolved in D. I water and NCM82 powders were added in the coating solution, stirred, filtered, dried filtered powders and calcination of black powder materials.

The effect of washing process on the structure change of NCM82 Ni-rich materials
The XRD data of all samples were performed measurement on the X-ray diffraction (XRD, Rigaku, SmartLab) with 2 θ in a range from 10 to 80 °and scanning mode of 0.3, (Cu target of 1.5412 Å ). Fig. 1 shows the XRD spectra of the bare NCM82, NCM82 materials were washed in D. I water, dried at 80 °C for 2 h (NCM-W80) and heated at 750 °C for 3 h (NCM-W750), ZrO 2coated NCM82 materials from Zr(SO 4 ) 2 solution without TA was dried at 80 °C for 2 h (Z 0.08 -80) and heated at 750 °C for 3 h (Z 0.08 -750). Fig. 1 (a, b) show the XRD pattern of NCM-W80 and NCM-W750 compared with pristine NCM82 sample, observed that the peak at (003) of NCM-W80 shifts to lower 2 θ (degree of shift peak, (2 θ ) is 0.04 °). Fig. 1 (c, d) shows the XRD pattern of the Z 0.08 -80 and Z 0.08 -750, observed that peak at (003) of Z 0.08 -80 had two 2 θ peaks at 18.74 °a nd 18.53 °. The peak at (003) of the NCM-W750 and Z 0.08 -750 shift to a higher angle close to the original peak position of the pristine sample, maybe due to the oxygen defects established in the octahedral structure of NiO 6 [2 , 3] .  Fig. 2 (a, b) shown the XRD pattern of the NCM82 powders were immersed in the different concentration of Zr(SO 4 ) 2 of 0,04, 0.08, 0.16 and 0.24 M for 5 min, after filtered, dried and calcinated, the samples were named Z 0.04 , Z 0.08 , Z 0.16 and Z 0.24 , respectively. The peak at (003) is moved to the higher angle 2 θ when increases concentration of Zr in the coating solution, due to the amount of Zr-coated increased. The Fig. 2 (c, d) show the XRD spectra of coating sample from 0.08 M Zr(SO 4 ) 2 with different TA concentration of 0, 0.1, 0.2, 0.3 and 0.4 M compared pristine sample, the samples were named Z 0.08 , Z 0.08 T 0.1 , Z 0.08 T 0.2 , Z 0.08 T 0.3 and Z 0.08 T 0.4 , respectively. The peak at (003) is shifted to the higher angle 2 θ when increases concentration of TA in the coating solution, TA could be agent controlling thickness of ZrO 2 -layers as well as the amount of Zr-precipitation on the host materials.

The characterization of surface modification for Ni-rich layered oxide cathode materials
The chemical composition on the surface of the pristine NCM82, Z 0.08 and Z 0.08 T 0.2 were determined by XPS analysis as shown in Fig. 3 , all XPS spectra were calibrated against the C 1 s binding energy at 285 eV. The XPS measurement has proceeded after Ar-etching 3 s ( Fig. 3 (a)) or 30 s ( Fig. 3 (b)). Z 0.08 and Z 0.08 T 0.2 show the characterization peaks at 184.10 eV (Zr 3d 3/2 ) and 181. 68 (Zr 3d 5/2 ), which was observed in the Z 3d spectra, and intensity of the Zr 3d 3/2 and Zr 3d 5/2 peaks with Z 0.08 T 0.2 is much higher than that these peaks in Z 0.08 sample at the same condition [1] . The one of the characterization of lithium impurity (Li 2 CO 3 ) was observed in O 1s spectrum (at 531.8 eV), the intensity of this peak in is decreasing for Z 0.08 and Z 0.08 T 0.2 compared with the bare sample. Surface morphologies of the bare NCM82, Z 0.08 and Z 0.08 T 0.2 were shown in Fig. 4 (a), the ZrO 2 coating layer on the surface of Z 0.08 T 0.2 is relatively uniformity, meanwhile, a coating materials layer on the surface of Z 0.08 is un-even distributed. For the bare sample, the white grain was observed that is the lithium impurities as a report of X. Xiong et al. [3] . In addition, Zr element is more evenly distributed on the surface of the Z 0.08 T 0.2 sample compared with bare sample [1] . Fig. 5 (a) shows the distribution thickness of the ZrO 2 on the surface of the Z 0.08 , Z 0.08 T 0.2 and Z 0.08 T 0.3 , which was collected from TEM image Fig. 5 (b, c, d). The thickness of coating materials layer was calculated by two software of excel (follow Pythagora's theorem as described in Fig. 5 (c)) and directly from ImageJ software. The ZrO 2 -thick is relative uniformity, which varied from 5.06 to 7.08 nm and the average thickness is about 5.75 nm. A ZrO 2 layer on the surface of Z 0.08 is varied from 1.42 to 3.96 nm and an average thickness of 2.75 nm. For the Z 0.08 T 0.3 sample, the thickness of a ZrO 2 layer varied from 5.9 to 13.4 nm and an average thickness of about 9.68 nm.

Effect of coating solution on the distribution ZrO 2 -thick coating layer
2.6. Effect of pH value of coating solution on the solubility of the lithium impurities on the surface of Ni-rich layered cathode structure Fig. 6 (a) shows the amount of Li impurities (LiOH/ Li 2 CO 3 ) with bare NCM82, washed NCM82, Z 0.08 and Z 0.08 T 0.2 sample. The concentration of Li impurities on the surface of the sample is decreased when the amount of TA increases in the coating solution. Videlicet, TA has supported ability dissolution of Li impurities and controlled pH value of coating solution as shown in Fig. 6 (b). Concretely, amount of Li impurities were eliminated in a washed sample of (29.02% Li 2 CO 3 , 80.74% LiOH), in Z 0.08 is (33.7% Li 2 CO 3 , 82.96% LiOH) and in Z 0.08 T 0.2 is (80.82% Li 2 CO 3 , 85.15% LiOH), compared with the bare sample.