DOI: 10.5061/dryad.mpg4f4rf3
title: Data from: Uniform pore structure enables negligible degradation in undoped and uncoated Ni-rich cathodes

description: Ni-rich layered oxide cathodes for lithium-ion batteries exhibit
 chemo-mechanical failures, with the consensus attributing this to
 high-voltage phase transitions. Existing mitigation strategies rely on
 compositional modifications (e.g., doping), nanostructuring (e.g.,
 coatings and primary particle engineering), and microstructure
 modifications, but these approaches increase synthesis complexity. Here,
 we demonstrate a simple synthesis strategy that enables exceptionally
 stable Ni-rich cathodes without doping, coating, or concentration
 gradients. We show that chemo-mechanical failure is closely linked to
 microstructural non-uniformity (specifically, nanoscale pores), stemming
 from limited contact between solid-state reactants during calcination. By
 increasing the LiOH melting rate, we enhance liquid-solid interfacial
 contact between precursors, resulting in uniformly evolved
 microstructures. This uniformity leads to excellent cycle life by
 dissipating strain energy and mitigating chemo-mechanical failure, even in
 the presence of high-voltage phase transition. Our findings challenge the
 prevailing belief that suppressing this phase transition and hierarchical
 material design are necessary for stable Ni-rich cathodes.
description: # Data from: Uniform pore structure enables negligible degradation in
 undoped and uncoated Ni-rich cathodes Dataset DOI:
 [10.5061/dryad.mpg4f4rf3](https://doi.org/10.5061/dryad.mpg4f4rf3) ##
 Description of the data and file structure * Echem.xlsx contains the raw
 electrochemical data used to generate Figs. 5a, 5b, and 5e of the paper,
 “Uniform pore structure enables negligible degradation in undoped and
 uncoated Ni-rich cathodes.” This file includes voltage profiles,
 differential capacity (dQ/dV) evolution over 100 cycles, and full-cell
 electrochemical performance for samples synthesized at heating rates of 2,
 5, and 10 °C/min. - TGA.xlsx contains the raw thermogravimetric analysis
 data for Figs. 1a and 2b. These data include TGA measurements of
 LiOH-H~2~O, (Ni~0.9~Mn~0.1~)(OH)~2~, and their physical mixture, as well
 as the evolution of TGA behavior as a function of heating rate. * XRD.xlsx
 contains the raw X-ray diffraction data for Figs. 1b, 1c, and 5c. This
 file includes in situ heating XRD data of the precursor mixture, the
 corresponding Rietveld refinement results, and operando XRD data collected
 from samples synthesized at heating rates of 2, 5, and 10 °C/min. - Each
 image file corresponds to optical microscopy (OM), scanning electron
 microscopy (SEM), and projection X-ray microscopy (PXM) results of samples
 synthesized under the conditions specified in the file name (temperature
 and heating rate). * Large-scale datasets used in the study, such as
 transmission X-ray microscopy and X-ray nano imaging data, are not
 deposited here due to their large file sizes. These datasets are available
 from the corresponding author upon reasonable request. ### Files and
 variables #### File: OM_380°C_2°Cmin.jpg **Description:** Optical
 microscopy image of the sample synthesized at 380 °C and 2 °C/min. ####
 File: OM_380°C_10°Cmin.jpg **Description:** Optical microscopy image of
 the sample synthesized at 380 °C and 10 °C/min. #### File:
 OM_420°C_2°Cmin.jpg **Description:** Optical microscopy image of the
 sample synthesized at 420 °C and 2 °C/min. #### File: OM_440°C_2°Cmin.jpg
 **Description:** Optical microscopy image of the sample synthesized at 440
 °C and 2 °C/min. #### File: OM_420°C_10°Cmin.jpg **Description:** Optical
 microscopy image of the sample synthesized at 420 °C and 10 °C/min. ####
 File: OM_440°C_10°Cmin.jpg **Description:** Optical microscopy image of
 the sample synthesized at 440 °C and 10 °C/min. #### File: XRD.xlsx
 **Description:** Raw X-ray diffraction (XRD) data used for in situ heating
 experiments, Rietveld refinement, and operando measurements of Ni-rich
 cathode materials synthesized under different heating rates. 1. Sheet:
 Fig. 1b * Columns labeled “x”: 2θ (degree) * Columns labeled “y”: XRD
 intensity (a.u.) 2. Sheet: Fig. 1c * Columns labeled “x”: Temperature (°C)
 * Columns labeled “y”: Crystallite size, crystallite volume, microstrain
 3. Sheet: Fig. 5c_2 °C.min, Fig. 5c_5 °C.min, and Fig. 5c_10 °C.min *
 Columns labeled “x”: 2θ (degree) * Columns labeled “y”: XRD intensity
 (a.u.) #### File: PXM_440°C_2°Cmin_1.tif **Description:** Projection X-ray
 microscopy (PXM) image of the first particle from the sample synthesized
 at 440 °C with a heating rate of 2 °C/min. #### File:
 PXM_440°C_2°Cmin_2.tif **Description:** Projection X-ray microscopy (PXM)
 image of the second particle from the sample synthesized at 440 °C with a
 heating rate of 2 °C/min. #### File: PXM_440°C_10°Cmin_2.tif
 **Description:** Projection X-ray microscopy (PXM) image of the second
 particle from the sample synthesized at 440 °C with a heating rate of 10
 °C/min. #### File: PXM_560°C_2°Cmin_2.tif **Description:** Projection
 X-ray microscopy (PXM) image of the second particle from the sample
 synthesized at 560 °C with a heating rate of 2 °C/min. #### File:
 PXM_560°C_10°Cmin_2.tif **Description:** Projection X-ray microscopy (PXM)
 image of the second particle from the sample synthesized at 560 °C with a
 heating rate of 10 °C/min. #### File: PXM_560°C_2°Cmin_1.tif
 **Description:** Projection X-ray microscopy (PXM) image of the first
 particle from the sample synthesized at 560 °C with a heating rate of 2
 °C/min. #### File: PXM_560°C_10°Cmin_1.tif **Description:** Projection
 X-ray microscopy (PXM) image of the first particle from the sample
 synthesized at 560 °C with a heating rate of 10 °C/min. #### File:
 TGA.xlsx **Description:** Raw thermogravimetric analysis (TGA) data for
 LiOH-H~2~O, (Ni~0.9~Mn~0.1~)(OH)~2~, and their physical mixture, including
 the evolution of mass change as a function of temperature under different
 heating rates. 1. Sheet: Fig. 1a * Columns A, C, E, G: Temperature (°C) *
 Columns B, D, F, H: Mass change (%) or differential mass change 2. Sheet:
 Fig. 2b * Columns A, C, E: Temperature (°C) * Columns B, D, F: dQ/dT
 (°C⁻¹) #### File: OM_560°C_2°Cmin.tif **Description:** Optical microscopy
 image of the sample synthesized at 560 °C and 2 °C/min. #### File:
 SEM_2°Cmin_100cycles.tif **Description:** Scanning electron microscopy
 (SEM) image of the sample synthesized at a heating rate of 2 °C/min after
 100 electrochemical cycles. #### File: PXM_440°C_10°Cmin_1.tif
 **Description:** Projection X-ray microscopy (PXM) image of the first
 particle from the sample synthesized at 440 °C with a heating rate of 10
 °C/min. #### File: OM_560°C_10°Cmin.tif **Description:** Optical
 microscopy image of the sample synthesized at 560 °C and 10 °C/min. ####
 File: SEM_10°Cmin_100cycles.tif **Description:** Scanning electron
 microscopy (SEM) image of the sample synthesized at a heating rate of 10
 °C/min after 100 electrochemical cycles. #### File: Echem.xlsx
 **Description:** Raw electrochemical data including voltage profiles,
 differential capacity (dQ/dV) evolution over 100 cycles, and full-cell
 performance for samples synthesized at heating rates of 2, 5, and 10
 °C/min. 1. Sheet: Fig. 5a * Columns A, D, G: Capacity (mAh g⁻¹) * Columns
 B, E, H: Voltage (V) 2. Sheet: Fig. 5b_2 °C.min * Columns A, C, E, G, I:
 Voltage (V) * Columns B, D, F, H, J: dQ/dV (mAh g⁻¹ V⁻¹) 3. Sheets: Fig.
 5b_5 °C.min, Fig. 5b_10 °C.min * Columns A, C, E, G, I: Voltage (V) *
 Columns B, D, F, H, J: dQ/dV (mAh g⁻¹ V⁻¹) 4. Sheet: Fig. 5e * Columns A,
 D, G: Cycle number * Column B: Capacity retention (%) * Column E: Voltage
 retention (%) * Column H: Coulombic efficiency (%) ## Code/software Any
 program that can open image files, such as JPG or JPEG, is recommended.
 Open-source options include GIMP, nomacs, and Paint. ## Access information
 Other publicly accessible locations of the data: * None Data was derived
 from the following sources: * This dataset was generated by the authors
 for this study.