Understanding the Stability of LiNi_0.5Mn_0.5O₂ as a Co-Free Positive Electrode

Abstract

To understand the stability of Co-free positive electrode materials, LiNi0.5Mn0.5O2 was synthesized with different amounts of lithium added during calcination. The valence states of the Ni and Mn transition metals of the prepared samples were determined through accurate stoichiometry analyses (via inductively coupled plasma optical emission spectrometry), magnetic moment measurements (via superconducting quantum interference device magnetometry), and element valence analyses (via X-ray spectroscopy in combination with Ar ion etching for depth profiling). Unexpectedly, the Ni and Mn transition metals in the interior and on the surface of the LiNi0.5Mn0.5O2 particles show different electrochemical properties. This clarifies the open questions on the Li deintercalation mechanism in LiNi0.5Mn0.5O2.

Effect of Subtle Changes in Ni2+/Ni3+ and Particle Surface Area in LiNi0.5Mn0.5−xCoxO2 (x = 0.1–0.3) Cathode Materials for Lithium-Ion Batteries

“…23,24 Overall, the relative amount of anti-site defects has a linear relationship with Ni 2+ concentration in Li[Ni 0.5 Mn 0.5−x Co x ]O 2 (x = 0.1-0.3) series. The reported anti-site defect concentration 17 (and the lattice parameters) of LiNi 0.5 Mn 0.5 O 2 (550) agrees well with the observed trend shown in Table I. Since all the studied cathode materials were synthesized at the same conditions including the calcination temperature, the only factor that can determine the amount of anti-site defects should be the Ni:Mn:Co.…”

Materials Towards the Development of Li Rechargeable Thin Film Battery

“…But the use of Co ions is not considered favourable at industrial level as Co has issues related with the abundance and cost (Gourley et al, 2020;. Thus, efforts for developing next generation Ni-rich layered oxide cathodes with no Co are underway (Liang et al, 2020;Liu et al, 2022;Yu et al, 2022).…”