Titanium Substitution Facilitating Oxygen and Manganese Redox in Sodium Layered Oxide Cathode

This dataset contains original PNG data from original research within the project EBEAM. Precisely, there are six final, complex Figures, below: Figure 1. Structure and composition of the NLMO and NLMTO. a,b) Rietveld refinement of XRD patterns. Extra peaks at 17-30° represent the existence of superstructure. c-e) Structure models. The prismatic Na coordination in d) and ABBA repeat stacking sequence of O in c) indicate the P2 structure. The models in e) show the special Li‐Mn and Li‐Mn‐Ti superstructures. f–g) EDS mapping images (Scale bar, 50 nm). h) Ti 2p XPS spectra. Figure 2. Structure evolution of the NLMO and NLMTO. a,b) Charge–discharge curves in the 1st cycle and corresponding in situ XRD patterns Figure 3. Charge compensation of the NLMO and NLMTO. a) The initial chargé-discharge curves. Three labeled states (Pristine, 4.5 and 1.5 V) were selected to test ex situ XPS. The charge compensation mechanism is also summarized in (a). b,c) Ex situ XPS O 1s spectra. d) The mole ratio of oxidized O2minus (On-minus) among the total oxygen signals. e) Ex situ XPS Mn 2p3-2 spectra. Figure 4. Electrochemical behaviors of the NLMO and NLMTO. a-c) The charge curves at 0.1C (1C is 200 mA g minus1), corresponding V versus dQ-dV patterns, and Q versus dV-dQ patterns. The labeled Mn‐redox and O‐redox in (b) and (c) are used to calculate their capacity contribution. d,e) Rate capacity and cycling performance at 0.5C. f,g) The calculated capacity of Mn‐redox and O‐redox driven from differential curves. h) Resistance from the SEI layer (RSEI) and charge transfer (RCT). Figure 5. Bulk and interphase structures of the NLMO and NLMTO after cycling. a) XRD patterns. b) STEM images. c,d) TEM images. e,f) O1s and F 1s XPS spectra. The XPS signals are composed of species from both the bulk structure and SEI layer. Figure 6. DFT calculations of the NLMO and NLMTO. a) The total, O 2p, and Mn 3d density of states (DOS). The Fermi energy (EF) level is set to be 0 eV. b) Schematic illustration of the energy levels. The red, blue, and orange arrow lines represent the locations of the top Mn4plus 3d t2g, O2minus 2p, and the bottom Mn4+ 3d eg orbitals respectively. Funding: This work was supported by following grants, National Natural Science Foundation of China (Grant No. 52071225 and 51672181), the Department of Human Resources and Social Security of Jiangsu Province (100 Talents Project); European Union’s Horizon Europe Research and Innovation Program under grant agreement No.101087143 (Electron Beam Emergent Additive Manufacturing (EBEAM)); REFRESH Research Excellence for Region Sustainability, and High-tech Industries project No. CZ.10.03.01/00/22 003/0000048 via an operational program transition.