Dual modification of LiNi0.6Co0.2Mn0.2O2 with MgHPO4 as a high-performance cathode material for Li-ion batteries. (21st December 2021)

• Record Type: Journal Article
• Authors: Ge, Wujie; Fu, Yuanxiang; Ma, Xianguo; Li, Xiang; Peng, Gongchang
• Is Part Of: Energy advances. Volume 1:Number 1(2022)
• Page Start: 28
• Page End: 37
• Publication Date: 2021-12-21
• Subjects: Periodicals; Fuel cells; Electrochemistry; Chemical engineering; Thermoelectricity; 621.31242
• DOI: 10.1039/d1ya00031d
• Languages: English
• ISSNs: 2753-1457

Abstract

Abstract : The surface lithium-ion conductive Li3 PO4 coating and bulk Mg 2+ gradient doping were detected for the modified NCM622 cathode materials. The interfacial instability and bulk structure degradation were suppressed by the simple dual modification. Abstract : MgHPO4 has been introduced as a reactant that interacts with LiNi0.6 Co0.2 Mn0.2 O2 (NCM622) to achieve the dual modification of Mg 2+ gradient doping and Li3 PO4 surface coating. The structure, morphology, elemental distribution, and electrochemical properties of the materials are elaborately explored using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. On the one hand, Mg 2+ gradient doping stabilizes the crystal structure of the Li + /Ni 2+ cation and minimizes its disorder. On the other hand, the coating of the fast lithium-ion conductor Li3 PO4 not only increases the rate of lithium-ion diffusion at the electrode–electrolyte interface but also protects the cathodic material and mitigates electrolyte corrosion. The dual-modified NCM622 cathode exhibits remarkable cycling performance, retaining 89.57% of its capacity after 200 cycles at 1C from 2.8 to 4.3 V and 79.03% after 100 cycles at 3C from 2.8 to 4.5 V. Additionally, the dual-modified cathode exhibits better electrode kinetics and a reversible capacity of 119.4 mA h g −1 at 10C. This straightforward dual modification technique improves the lithium-ion diffusion kinetics at the interface while also stabilizing the internal crystal structure of Ni-rich cathode materials.