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Enhanced Electrochemical Performance of Zinc Phosphate Coated Ni-Rich LiNi0.8Co0.1Mn0.1O2 Cathode for Li-Ion Battery(PDF)

MATERIALS CHINA[ISSN:1674-3962/CN:61-1473/TG]

Issue:
2021年第07期
Page:
553-560
Research Field:
Publishing date:

Info

Title:
Enhanced Electrochemical Performance of Zinc Phosphate Coated Ni-Rich LiNi0.8Co0.1Mn0.1O2 Cathode for Li-Ion Battery
Author(s):
WANG ZhentaoGU HongWANG Juan
(Xi’an Key Laboratory of Clean Energy,Xi’an University of Architecture and Technology,Xi’an 710016, China)
Keywords:
Lithium ion battery Ni-rich cathode material Zn3(PO4)2 coating modification cycle performance rate performance
CLC:

PACS:
TM912
DOI:
10.7502/j.issn.1674-3962.202005031
DocumentCode:

Abstract:
Nickel-rich cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) has the advantages of low cost and large reversible capacity, so it has great potential for commercial application and becomes a hot spot for extensive research of new energy materials. However, high nickel content of Ni-rich cathode materials leads to increased surface structural instability and reduced interplanar spacing, as a result the cathode material shows poor cycle performance and rate performance in the commercial application. Based on the preparation of pure NCM811 by coprecipitation method, PVP (polyvinylpyrrolidone) assisted zinc phosphate coating NCM811 cathode material were synthesized. XRD patterns indicate that I(003)/I(104) of the coated sample with 3% ZnO addition (mass fraction, named NCM2) is the largest, and its c/a is bigger than that of the pristine, which means NCM2 has a lower degree of Li+/Ni2+ mixing. At the same time, zinc ion insertion improves the atomic scattering ability in the (003) plane. X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM), energy dispersive spectrometer(EDS)results show zinc phosphate is uniformly coated on the particle surface of cathode materials. The capacity of NCM2 after 100 cycles at the current density of 0.1C is 191 mAh·g-1, and the capacity retention rate is 92%, however, the capacity retention rate of the pure sample is 87%. At 5C current density, the discharge capacity of NCM2 is 43% higher than that of the pure sample. The cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)test results show that the electrochemical polarization of the cathode material decreases and the lithium ion diffusion rate increases after coating, As a result, the cycle performance and the rate performance of zinc phosphate coated NCM811 cathode material are improved.

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Last Update: 2021-06-30