Raman Microspectrometry Applied to the Study of Electrode Materials for Lithium Batteries

Development of In Situ Cross-Sectional Raman Imaging of LiCoO₂ Cathode for Li-ion Battery

“…Before the charge/discharge operation, two peaks are observed at 596 cm ¹1 and 485 cm ¹1 , which correspond to Co-O stretching, A 1g , and O-Co-O bending, E g , modes of LiCoO 2 , respectively. 13,19 The intensities of the two peaks are almost the same, while A 1g is generally stronger than E g in the literature. This is probably due to the direction of the crystal plane of the LiCoO 2 particle.…”

“…To analyze the structure of the electrode in connection with the reaction, various methods, such as nuclear magnetic resonance (NMR), 8,9 X-ray diffraction (XRD), 10,11 X-ray absorption fine structure (XAFS), scanning Auger microscopy (SAM), 12 and Raman spectroscopy, [13][14][15][16][17][18][19][20][21] have been used. Also, the three-dimensional structure of the vacancy in electrodes has been well-studied by both simulation, 22,23 and instrumental analysis.…”

“…Hence, many efforts have been made to develop in situ techniques. [13][14][15][16][17][18][19][20][21] However, most of them only measure the spectra. Therefore, it has not been possible to obtain the spatial distribution of the degree of reaction process in a single charge/discharge cycle.…”

Ultrahigh‐Power Pseudocapacitors Based on Ordered Porous Heterostructures of Electron‐Correlated Oxides

“…In the XRD patterns of NP V 2 O 3 /MnO 2 , the peaks at 2 θ = 18.5°, 30.9°, and 36.1° correspond to the (111), (220), and (311) plane of spinel‐type MnO 2 , in addition to the characteristic peaks of NP V 2 O 3 scaffold with depressed intensity, which is due to the coating of MnO 2 layer with poor crystallinity (Figure S4b, Supporting Information). The interfacial structure of V 2 O 3 /MnO 2 , as shown in the HRTEM image (Figure 2f), indicates the epitaxial growth of spinel MnO 2 nanocrystals on V 2 O 3 network surfaces with the assistance of stabilizing Na + cation and the further formation of chemical V—O—Mn bonding at the interface during the heat treatment process 45, 46. As a consequence, the Raman spectrum of the heat‐treated NP V 2 O 3 /MnO 2 electrode exhibits a characteristic Raman peak at 842 cm −1 with dramatically enhanced intensity (pink curve in Figure 2c),46 in addition to peaks from both corundum V 2 O 3 and spinel MnO 2 in the pristine one (green curve in Figure 2c).…”

A Porous TiO2Electrode Prepared by an Energy Efficient Pyro-Synthesis for Advanced Lithium-Ion Batteries

“…Since their electrochemical properties and safety issues are critically dependent on the electrode materials, much effort has been made to develop alternative anodes based on transition metal oxides in an attempt to produce safer LIBs exhibiting higher performance. [8][9][10][11][12][13][14][15][16][17][18] In this regard, anatase-type TiO 2 anodes with a relatively high voltage potential (∼1.7 V) vs. Li/Li + , high capability, thermodynamic stability, low safety risks, and costs have been widely investigated.15-21 Despite these advantages, the low electronic conductivity and lithium diffusivity within the lattice restricts the application of TiO 2 as a high-power anode.22-24 For instance, the theoretical specific capacity of TiO 2 is high (335 mAh g −1 ); however, in reality, only 0.5 mol lithium (equivalent to a specific capacity of 168 mAh g −1 ) is reversibly inserted per formula unit of TiO 2 consisting of micro-sized particles. The established strategy to overcome this drawback is to develop composite/coating with metals (Cu, Sn, Ag, Au), metal oxides (SnO, SnO 2 , RuO 2 ) and carbonaceous materials as electrically conductive agents or functional components.…”