Effects of Coating with Gold on the Performance of Nanosized LiNi[sub 0.5]Mn[sub 1.5]O[sub 4] for Lithium Batteries

Abstract

The electrochemical behavior of an Au-coated LiNi 0.5 Mn 1.5 O 4 nanospinel in lithium cells was studied at two different temperatures ͑25 and 50°C͒ and at five charge/discharge rates ͑C/6, C/4, 2C, 4C, and 8C͒. Two different coating methods were tested and the resulting products characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. One method, which involved treatment with HAuCl 4 in the presence of HCOH as reductant, resulted in poorer cell performance irrespective of the particular charge/discharge regime used, probably by effect of the attack on the material degrading its surface during the coating process. The other coating method involved evaporating Au on the spinel, the effect of coating on cell performance being dependent on both temperature and the charge/discharge rate. Thus, low rates ͑C/6, C/4͒ increased the capacity delivered by the cell at 50°C by ca. 20% relative to the bare spinel. This beneficial effect can be ascribed to the coating layer altering the electrolyte decomposition and the spinel particles being protected from attack by the species formed in the electrolyte decomposition. At high rates ͑2C, 4C͒, however, electrolyte decomposition played a minor role and crossing of the gold layer by lithium ions raised an energy barrier to be overcome. Under these conditions, the capacity delivered by the cell was markedly degraded irrespective of the temperature used.

Research progress in high voltage spinel LiNi0.5Mn1.5O4 material

“…Lithium metal oxides were coated with various oxides and phosphates and demonstrated improved capacity retention during cycling. Surface modifications of LiNi 0.5 Mn 1.5 O 4 spinel material by coating various oxides and phosphates such as ZnO [87][88][89][90], SnO 2 [91], Li 3 PO 4 [92], and different metal treatments such as Zn [93], Au [94], Ag [95] have been widely investigated. In the case of ZnO-coated LiNi 0.5 Mn 1.5 O 4 , the ZnO-coated electrode delivered the capacity of 137 mA h g −1 without any capacity loss even after 50 cycles at 55 • C as shown in Fig.…”

High electrochemical performances of α-MoO 3 @MnO 2 core-shell nanorods as lithium-ion battery anodes

“…a-MoO 3 @MnO 2 core-shell nanorods can offer a larger material/electrolyte contact area and accommodate Secondly, the good cyclability of a-MoO 3 @MnO 2 core-shell nanorods can be ascribed to their one-dimensional core-shell nanostructures. The one-dimensional core-shell structures usually possess unique physical and chemical characteristics to improve the performance of anode materials, which stems from restricting the formation of a solid electrolyte interphase (SEI), volume expansion, shortened electronic/ionic transport lengths, avoiding the agglomerations and pulverization of materials [7,8,41]. Thirdly, nanodispersed Mo and Mn metal particles can provide good conduction pathways for electronic conductivity along with shorter path for lithium diffusion [42][43][44].…”

“…Therefore, new lithium storage anode materials with high capacity need to be explored. Recently, various metal oxide nanostructures have been widely investigated as LIBs anodes [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Among these metal oxides materials, MoO 3 is an attractive anode material for LIBs.…”

Temperature-dependent oxygen behavior of LixNi0.5Mn1.5O4 cathode material for lithium battery

“…34,35 Previously we characterized the structural properties of Li from the neutron diffraction measurements. 36 And one of the results showed that, with the extraction of Li from LNMO, the amount of oxygen decreased in such a way that both the amount and the oxidation state of Ni and Mn cations are taken into account.…”