Enhanced Stability of LiCoO[sub 2] Cathodes in Lithium-Ion Batteries Using Surface Modification by Atomic Layer Deposition

Abstract

Ultrathin atomic layer deposition (ALD) coatings enhance the performance of lithium-ion batteries (LIBs). Previous studies have demonstrated that LiCoO2 cathode powders coated with metal oxides with thicknesses of ∼100 to 1000Å grown using wet chemical techniques improved LIB performance. In this study, LiCoO2 powders were coated with conformal Al2normalO3 ALD films with thicknesses of only ∼3 to 4Å established using two ALD cycles. The coated LiCoO2 powders exhibited a capacity retention of 89% after 120 charge–discharge cycles in the 3.3–4.5 V (vs Li/Li+ ) range. In contrast, the bare LiCoO2 powders displayed only a 45% capacity retention. Al2normalO3 ALD films coated directly on the composite electrode also produced improved capacity retention. This dramatic improvement may result from the ultrathin Al2normalO3 ALD film acting to minimize Co dissolution or reduce surface electrolyte reactions. Similar experiments with ultrathin ZnO ALD films did not display enhanced performance.

Surface chemistry of LiNi0.5Mn1.5O4 particles coated by Al2O3 using atomic layer deposition for lithium-ion batteries

“…[ 21,22] during the initial charge/discharge cycle is observed in Figure 2d. However, at higher numbers of charge-discharge cycles, all the Al 2 O 3 ALD coated LNMO electrodes exhibit much higher coulombic efficiencies than the bare LNMO electrodes do.…”

Evaluating the performance of nanostructured materials as lithium-ion battery electrodes

“…While there has been a distinct move for alternative electrode hosts (LiCoO2 is both toxic and relatively expensive to produce), research has still considered a number of practical LiCoO2 architectures with high voltage and good rate performance [249][250][251][252][253][254][255][256][257]. In the interest of capacity retention, commercial LiCoO2 cells typically adopt a reversible capacity to 0.5 Li + by setting the upper-cut off potential to 4.2 V, thus yielding working capacities approaching 150 mA h g -1 [258].…”

“…Limiting the occurrence of potentially poisonous interactions is therefore highly advantageous to the cycle life of the electrode. Recent studies have demonstrated nanometre-scale coatings of inactive Al2O3 on LiCoO2 nanoparticles [256,262,263]. In the first example, LiCoO2 particles prepared by a molten-salt synthesis using CoO, LiOH and KNO3, were subjected to consecutive ALD cycles, each depositing a thin-film of Al2O3 ranging between 1.1-2.2 Å in thickness.…”

Increase of Mobility of Ions in Li-Ion Batteries by Ultrathin Phonon Coatings of Electrodes

“…whose dimension is equal to the dimension of thermal capacitance, and nondimensional properties are compared: Fig.3 shows relative (nondimensional) thermal capacitances of bulk (b) and film-structure (f) subject to the relative temperature x, for It can be seen that in low-temperature region (Fig.4a) thermal capacitance of film is lower than that of massive specimens, whereas at the intermediate temperatures situation is reversed [5]. The intersection point of two curves at low temperatures is moving -with increase of film-thickness -towards lower temperatures (Fig.4a -> c).…”

“…ALD requires only a minimum quantity of precursors and ALD coatings are compatible and provide control of atomic thickness. ALD could be a promising alternative manner for coating electrode materials for LIBs [5].…”