Electrochemistry and Structural Chemistry of LiNiO2 (R3m) for 4 Volt Secondary Lithium Cells

Abstract

The synthesis and characterization of LiNiO2 for a 4 V secondary lithium cell was done. The LiNiO2 was prepared by ten different methods and characterized by x-ray diffraction and electrochemical methods. LiNiO8 prepared from LiNO3 and NiCO3 [or Ni(OH)2] exhibited more than 150 mAh 9 g-1 of rechargeable capacity in the voltage range between 2.5 and 4.2 V in 1M LiC104 propylene carbonate solution. The reaction mechanism was also examined and explained in terms of to~otactic reaction. Lithium nickelate(III) (R3m; a = 2.88 A, c = 14.18 A in hexagonal setting) was oxidized to nickel dioxide (R3m; a = 2.81/~, c = 13.47 A) via Lil_=NiO2 (0.25(2) _-< x _-< 0.55(2)) having a monoclinic lattice (C2/m). The nickel dioxide could be reversibly reduced to lithium nickelate(III). Factors affecting the electrochemical reactivity of LiNiO2 are given and the possibility of using LiNiO2 for 4 V secondary lithium cells is described.

Tuning charge–discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

“…The three-dimensional (3D) expansion during delithiation for the layered cathodes is quite abnormal. It is well known that parameters a and b for most of LiMO 2 (M ¼ Co, Ni and Mn) materials decrease, while the parameter c increases during delithiation [7][8][9]11 (Table 1). The contracting a and b values for these materials are attributed to the decreasing cation radius of transition metal at higher valence states.…”

“…The layer-structured LiMO 2 has the theoretical capacities B270 mAh g À 1 ; however, only B140-150 mAh g À 1 reversible capacity can be practically utilized 6 with a cutoff voltage of B4.2-4.3 V. If the cells could be charged to higher voltages without damaging the structure, higher practical energy density (with high capacity and voltage) would be obtained. Unfortunately, when charge voltage limit is increased above 4.3 V, the reversible capacity in subsequent cycles fades seriously because of the structural degradation caused by high voltage charging [7][8][9][10] . Therefore, redesigning the chemical contents and crystal structures to suppress such structural degradation will open a new approach for developing high energy density cathode materials with long cycle life.…”

Surface properties of LiCoO2, LiNiO2 and LiNi1−xCoxO2

“…To explain these results, we turn to studies on the lithium bulk deintercalation of hexagonal LiNiO 2 , a process which is generally reversible down to concentrations of approximately Li 0.3 NiO 2 [74]. The process is complicated by the tendency for nickel to substitute for lithium as Ni 2+ within the lithium 〈1 1 1〉 planes, which hinders the lithium mobility and creates nickel-excess nonstoichiometry within the bulk phase.…”

“…However, one structure observed on severely delithiated materials involves an alteration in stacking structure along 〈1 1 1〉 from O-Li-O-Ni-O, etc. of the ideal stoichiometric structure to include clustering of O-Ni units, that is OLi-O-Ni-O-Ni-O-Li [74]. Thus, there is a natural tendency toward creation of a "NiO"-like environment for nickel cations even in the LiNiO 2 bulk.…”

Synthesis and Properties of Nanoparticle Li[Li0.2Mn0.54Ni0.13CO0.13]O2Cathode Material by Coprecipitation Method with Non-aqueous Medium

“…Cation mixing is known to deteriorate the electrochemical performance of the above layered compound. The integrated intensity ratio of I003/I104 (R) is sensitive to the cation mixing [11,12]. Researchers often used high intensity ratio of I003/I104 (R) to indicate the cation mixing of the layered structure [13].…”