Rational design of redox active amorphous Ni-Mn phosphate anchored on vertical graphene nanohills (VGNHs) for solid-state energy storage device

An Interfacial Engineering Approach of Flower-like Li+ Preintercalated Co–Cu Phosphate for Solid-State Hybrid Energy Storage Device

“…In this study, the distinctive characteristic peaks at 457, 555, 595, and 650 cm –1 correspond to the Cu–O vibration mode. − In addition, well-distinguished Co–O and O–Co–O Raman peaks were detected at 169, 200, 222, 290, 333, 380, 457, 555, 595, and 650 cm –1 . − Interestingly, the peaks at 457, 555, 595, and 650 cm –1 indicate similar chemical bonding in Cu–O, Co–O, and the combined Co–Cu–O. However, a comprehensive analysis of Co–Cu–O revealed a slight peak shift of some cm –1 , and peak intensities were also enhanced when compared to those of pristine Co–O and Cu–O, plausibly due to coordination interactions between Co and Cu in bimetallic samples, including Li as an alkali metal. , Moreover, the strong and sharp Raman peaks at 870, 953, 999, 1045, and 1077 cm –1 for all prepared samples are ascribed to the asymmetric O–P–O stretching, symmetric stretching, and vibrational mode of the PO 4 3– group. , Similarly, the peaks in the 3073–3390 cm –1 range are ascribed to adsorbed water (vibration mode of the −OH group). − No other bands were observed in any of these spectra except for the Co–O, Cu–O, and Co–Cu–O vibrations, indicating the successful synthesis of Li + preintercalated Co–Cu phosphate materials.…”

“…42,46 In addition, the O 1s XPS profiles of the Li + -free and Li + -intercalated CoCuP electrodes (Figure 2f) show three deconvoluted peaks at 529.2 (O1), 530.9 (O2), and 532.4 eV (O3), attributed to metal−oxygen, phosphate, or phosphorus− oxygen and −OH bonds, respectively. 41 Overall, Li ions were effectively incorporated into the host material, as indicated by the peak of the Li ions in the spectra of the Li-CoCuP4 thin film. Additionally, XPS analyses verified that pristine (CoCuP) and Li + preintercalated (Li-CoCuP4) Co−Cu phosphates were successfully obtained on the NF substrate.…”

“…In the XPS spectrum of Cu 2p (Figure d), the peak at 934.8 eV (Cu 2p 3/2 ) corresponds to Cu 2+ and is in tandem with two satellite peaks at 938.7 and 943.0 eV, assigned as “Sat.” , Similarly, the sharp Cu 2p 1/2 peak at 954.7 eV corresponds to Cu 2+ , whereas the two satellite peaks (Sat.) at 958.9 and 962.5 eV are assigned to Cu 2p 1/2 . , The peaks of Co 2p 3/2 and Cu 2p 3/2 in the aforementioned XPS profiles (Co 2p and Cu 2p) were slightly shifted toward lower binding energies (0.20 eV) in the spectra of the Li-CoCuP4 thin film due to Li-ion preintercalation, which indicates that Co/Cu was reduced by accepting electrons during the preintercalation process. , Moreover, the P 2p peak was observed at 133.1 eV for the CoCuP and Li-CoCuP4 thin films (Figure e), which indicates the existence of a phosphate (PO 4 3– ) group with P–O bonding. , In addition, the O 1s XPS profiles of the Li + -free and Li + -intercalated CoCuP electrodes (Figure f) show three deconvoluted peaks at 529.2 (O1), 530.9 (O2), and 532.4 eV (O3), attributed to metal–oxygen, phosphate, or phosphorus–oxygen and −OH bonds, respectively . Overall, Li ions were effectively incorporated into the host material, as indicated by the peak of the Li ions in the spectra of the Li-CoCuP4 thin film.…”