Improved Rate Capability and Thermal Stability of LiNi0.5Co0.2Mn0.3O2 Cathode Materials via Nanoscale SiP2O7 Coating

Abstract

LiδPyOz–coated LiNi0.5Co0.2Mn0.3O2 cathode materials doped with P and Si ions were prepared by direction reaction of LiOH and SiP2O7-coated Ni0.5Co0.2Mn0.3(OH)2 precursors. The coated cathodes exhibited quite impressive results; rate capability was improved by almost 100% at a 7 C rate compared to pristine LiNi0.5Co0.2Mn0.3O2. Furthermore, the amount of heat generation at 4.5 V charge cut-off as a result of the evolution of oxygen was reduced by 79%, compared to pristine LiNi0.5Co0.2Mn0.3O2 sample.

Effects of lithium-active manganese trioxide coating on the structural and electrochemical characteristics of LiNi0.5Co0.2Mn0.3O2 as cathode materials for lithium ion battery

“…on the particle surface in the form of Li 2 O/LiOH, according to our previous reports [9][10][11][12][14][15][16][17][18]. The pH value of LH6 is lower than that of the NMC, indicating that the Li 2 MnO 3 coating can relieve the negative effect of lithium residues under neutral modified environment.…”

“…Surface modification has been demonstrated as an efficient approach to enhance the electrochemical performance of NMC [10,11,[16][17][18].…”

“…Considering that the pristine materials are very sensitive to modified processes, particularly to the pH values; and that the effect of surface modification is also strongly dependent on the concentration of coating material, a detailed study for Li 2 MnO 3 coating should be conducted urgently [18,22,[25][26][27]36].…”

Multifunctional Li2O-2B2O3 coating for enhancing high voltage electrochemical performances and thermal stability of layered structured LiNi0.5Co0.2Mn0.3O2 cathode materials for lithium ion batteries

“…4a, the XPS spectra of Ni 2p3/2 of bare and LBO2 samples confirm that the oxidation state of Ni is a mixture of Ni 2+ and Ni 3+ , which agrees with previous results. [33][34][35] In addition, the binding energy peaks of Co2p 3/2 and Mn2p 3/2 (Fig.4b-c) are 780.19 eV and 642.59 eV, respectively. These values suggest that the valence state of element Co and Mn in the both samples are tetravalent and trivalent, quite in accord with earlier reported values.…”

Improvement of high voltage electrochemical performance of LiNi0.5Co0.2Mn0.3O2 cathode materials via Li2ZrO3 coating

“…Till now, fluorides, phosphates, and metal oxides such as AlF 3 , SiP 2 O 7 and TiO 2 are confirmed as an effective strategy to achieve this target [6][7][8]. These studies suggest that the presence of the coating can isolate the bulk materials from the electrolyte, thus the cathode material surface can be protected from electrolyte attack during charge-discharge process.…”