Superior electrochemical properties of Zirconium and Fluorine co‐doped Li1.20[Mn0.54Ni0.13Co0.13]O2 as cathode material for lithium ion batteries

Crystallography of Active Particles Defining Battery Electrochemistry

“…Techniques to provide insight into the chemical environment within/of electrode active particles were relatively less common compared to structural techniques. In conjunction with SEM [28][29][30] and STEM, [31] energy dispersive X-ray spectrometry (EDXS) is frequently used for tracing spatial elemental heterogeneity, such as the surface migration of nickel within a nickel manganese cobalt (NMC) oxide cathode, leading to the formation of rock salt structures creating lithium-ion diffusion barriers. [32] The ability of X-ray photoelectron spectroscopy (XPS) to determine oxidation state is important for the development of high voltage cathodes and to establish their electrochemical reversibility.…”

“…[160] A similar impact was observed with the doping of zirconium and fluoride ions into an NMC cathode to enhance cycling stability due to the increased bond strengths of Zr─O and F─O bonds; initial discharge capacity at 5 C was 40 mAh g −1 with a capacity retention 9.6% greater at a cycling rate of 2 C. Increased electrochemical performance was inferred from Rietveld refinement of XRD data as cation disorder was shown to be reduced, lattice regularity enhanced and c/a lattice parameter ratio increased highlighting the widening lithium ion diffusion channels. [31] An informed mineral choice enhancement (as in Figure 1) was carried out on a titanium doped lithiated cobalt phosphate (LiCo 0.9 Ti 0.05 PO 4 ) cathode; Ti 4+ ions were chosen as to minimize the formation of electrochemically inactive Co 3 O 4 and to create vacancies in Co sites within the olivine crystal structure to promote lithium-ion diffusion. Doping with titanium ions was shown to enhance capacity as XANES showed an increase in Co oxidation state of +0.13, promoting the +2 electrochemically active state of Co ions and increasing capacity retention to 72% after 100 cycles compared to 50% for the non-doped sample.…”

“…[ 160 ] A similar impact was observed with the doping of zirconium and fluoride ions into an NMC cathode to enhance cycling stability due to the increased bond strengths of Zr─O and F─O bonds; initial discharge capacity at 5 C was 40 mAh g −1 with a capacity retention 9.6% greater at a cycling rate of 2 C. Increased electrochemical performance was inferred from Rietveld refinement of XRD data as cation disorder was shown to be reduced, lattice regularity enhanced and c/a lattice parameter ratio increased highlighting the widening lithium ion diffusion channels. [ 31 ] An informed mineral choice enhancement (as in Figure 1) was carried out on a titanium doped lithiated cobalt phosphate (LiCo 0 . 9 Ti 0 .…”