Data for the publication: High performance of porous, hierarchically structured P2- Na0.6Al0.11 – xNi0.22 – yFex+yMn0.66O2 cathode materials

Data sets: SEM-images, EIS, ex situ XRD, operando XRD, electrochemical cycling.

Abstract: Sodium-ion-batteries (SIB) are a low-cost alternative to currently used lithium-ion batteries (LIB) but suffer from poor cycling stability. Spray drying provides porous, hierarchically structured particles of cathode active material (CAM) in large amounts, suitable for up-scaling. Changing the chemical composition of the Na0.6Al0.11–xNi0.22–yFex+yMn0.66O2 layered oxides under identical synthesis conditions leads to differences in particle morphology, conductivities, sodium vacancy ordering and phase transition, therefore influencing the electrochemical performance via several mechanisms. Here, a broad overview on these changes for samples with variable nickel and iron content is presented. With increasing iron content, the particle porosity is reduced and lower of initial capacity is received for most cycling windows. Substituting half of the original Ni amount with Fe still leads to high capacities and improved cycling stability. The influence of Al as electrochemical inactive element becomes visible in stabilised cycling stability as well.