On the electrochemical properties of the Fe–Ti doped LNMO material LiNi_0.5Mn_1.37Fe_0.1Ti_0.03O_3.95

Abstract

LiNi0.5Mn1.5O4 (LNMO) based spinel cathode materials for lithium-ion batteries are promising alternatives to the widely used mixed transition-metal layered Li(Ni,Co,Mn)O2 (NCM) oxides. LNMO is cobalt free and thus cost efficient,...

Coating versus Doping: Understanding the Enhanced Performance of High‐Voltage Batteries by the Coating of Spinel LiNi0.5Mn1.5O4 with Li0.35La0.55TiO3

“…[33]), a lattice parameter of, e.g., 816.4 pm [ 34 ] to 817.0 pm [ 35 ] are expected. As already discussed in detail for very similar materials back in 1993 by Feltz et al., [ 36 ] advocated by Cabana in the recent LNMO debate, [ 34,37,38 ] and concluded from our preceding work, [ 39 ] the higher Mn(III) content most likely is a side effect of the formation of the Ni‐rich secondary phase, coming along with a Ni‐depletion of the LNMO phase: $$\[ \begin{array}{*{20}{c}}{{\rm{LiNi}}_{0.5}^{{\rm{II}}}{\rm{Mn}}_{1.5}^{{\rm{IV}}}{{\rm{O}}_4} \rightleftharpoons {\rm{LiNi}}_{0.5 - y}^{{\rm{II}}}{\rm{Mn}}_{1.5 - y}^{{\rm{IV}}}{\rm{Mn}}_{2y}^{{\rm{III}}}{{\rm{O}}_4} + {\rm{L}}{{\rm{i}}_x}{\rm{N}}{{\rm{i}}_{1 - x}}{\rm{O}} + {{\rm{O}}_2}}\end{array} \]$$According to Equation (), chemical equilibrium shifts to the right side when calcination is carried out above the decomposition temperature (often referred to as the oxygen release temperature) and to the left for lower calcination temperatures. However, the back reaction may be limited by excessive phase segregation and kinetic restraint.…”

“…[33]), a lattice parameter of, e.g., 816.4 pm [34] to 817.0 pm [35] are expected. As already discussed in detail for very similar materials back in 1993 by Feltz et al, [36] advocated by Cabana in the recent LNMO debate, [34,37,38] and concluded from our preceding work, [39] the higher Mn(III) content most likely is a side effect of the formation of the Ni-rich secondary phase, coming along with a Ni-depletion of the LNMO phase:…”

“…This is problem further amplified by the circumstance that newly formed domains of Li x Ni 1−x O are likely to be amorphous or nanocrystalline and thus are not visible in the XRD patterns. [39] However, powder X-ray diffraction is not only a suitable method to obtain information on the calcining temperaturedependent shift of the lattice parameter, but also can provide detailed information concerning for LNMO coating or doping effects: the lattice parameters of LNMO samples coated with 0.5 and 3% LLTO are likewise depicted in Figure 4a (red and blue marks). It becomes obvious, that for 300 °C and 500 °C the LNMO lattice parameters are literally the same for coated and uncoated samples, which indicates, that there is very little or no interaction of the bulk LNMO with the Ti and La-rich coating layer.…”

Improved Kinetics in Spinel-Related 5 V Positive Electrode Materials by Changing Lithium Insertion Schemes for Lithium-Ion Batteries

“…Although the lattice parameter of their single Fe-doped LiNi 0.42 Mn 1.5 Fe 0.08 O 4 sample of 8.18556 Å was large enough to prove Fe substitution in comparison to 8.1683(4) Å of LNMO and the structure was characterized with respect to the cation disordering at the 16­(d) sites, the surface segregation of Fe ions in their sample suggests that 0.08Fe seems to be too high to substitute Fe for Ni ions in LNMO. The co-doping of Fe and Ti ions in the LNMO of LiNi 0.5 Mn 1.37 Fe 0.1 Ti 0.03 O 3.95 was reported by Stüble et al., which was prepared by heating at 900 °C for 20 h and then at 600 °C for 30 h in air . Their samples were reported to be completely or predominantly disordered, in which the Fe and Ti co-doping effectively suppressed the formation of well-ordered crystal domains.…”

“…Lattice parameters of their samples of x = 0.05 and 0. 49 Their samples were reported to be completely or predominantly disordered, in which the Fe and Ti co-doping effectively suppressed the formation of wellordered crystal domains. The lattice parameter of their sample was 8.1861(3) Å, which is comparable to that of our LNMO-FT sample, 8.1880(0) Å.…”