The Influence of Ultrathin Amorphous ALD Alumina and Titania on the Rate Capability of Anatase TiO₂ and LiMn₂O₄ Lithium Ion Battery Electrodes

Abstract

Interface modification is a heavily investigated method of extending the lifetime of lithium ion batteries. While many studies have explored the effect of interface coating on the lifetime, the rate capability is often overlooked. In this study, the authors investigated the influence of ultrathin (<10 nm) atomic layer deposition (ALD) coatings of amorphous Al2O3 and amorphous TiO2. It is found that, on thin‐film anatase TiO2, the rate capability is unaffected by an amorphous TiO2 coating since it does not pose an additional impedance on the system, while Al2O3 coatings are detrimental for the rate performance due to the 1.5 × 1012 Ω cm resistivity toward lithium ions. A thicker than 2 nm ALD Al2O3 film is found to block lithium transfer completely, resulting in a purely capacitive film. Solvent oxidation is studied on thin‐film LiMn2O4. The authors demonstrate that both coatings can partially solve the solvent decomposition. However, the kinetic bottleneck posed by 1 nm Al2O3 is still greater than the uncoated LiMn2O4, leading to worsened rate capability. ALD TiO2 on the other hand can prevent most of the solvent decomposition, resulting in smoother electrodes. The absence of the decomposition layer and lithium conducting properties of the ALD TiO2 films results in an improved rate capability for the ALD TiO2 coated electrode.

Recent Progresses and Development of Advanced Atomic Layer Deposition towards High-Performance Li-Ion Batteries

“…As for coating approaches, the ALD, in sharp comparison with the conventional mechanical mixing and sol-gel methods, affords extraordinary homogeneous cladding layer on the surface with precisely regulated down to sub-nanometers levels [ 5 , 164 ]. In this part, we comprehensively summarize the surface engineering via the ALD for cathode materials including layered cathodes, such as LiCoO 2 [ 111 , 112 , 118 , 148 , 149 ], LiNi x Mn y Co z O 2 [ 113 , 114 , 119 , 154 , 155 , 156 , 157 ], and Li-rich x Li 2 MnO 3 ·(1 − x )LiMO 2 (M = Mn, Ni, Co) [ 161 , 162 , 163 ], and spinel cathodes, such as LiMn 2 O 4 [ 150 , 151 , 152 , 153 ] and LiNi 0.5 Mn 1.5 O 4 [ 52 , 158 , 159 , 160 ], as listed in Table 3 . After careful observation in Table 3 , we can discover that the compounds serving as ALD coating layer for cathode materials can be mainly divided into four categories: metal oxides (Al 2 O 3 [ 118 , 119 , 152 , 154 , 155 , 156 , 159 , 161 , 163 , 165 , 166 ], TiO 2 ...…”

Al2O3-coated Li1.2Mn0.54Ni0.13Co0.13O2 nanotubes as cathode materials for high-performance lithium-ion batteries

“…The results showed that the surface coating materials exhibited improved rate capability. 22 Laskar et al prepared MgO-coated Li[Ni 0.5 Mn 0.3 Co 0.2 ]O 2 (NMC) cathode by atomic layer deposition method. The results showed that cyclic performance was signicantly improved.…”

Improved potassium ion storage performance of graphite by atomic layer deposition of aluminum oxide coatings

“…Although the capacities of other coated samples are inferior to 20‐ALD‐NG, they are still higher and more stable than bare NG. Thus, it can be speculated that the appropriate ALD coating has a beneficial effect on K + storage, but the too thick Al 2 O 3 layer oppositely increases the resistivity of K ions …”

“…Thus, it can be speculated that the appropriate ALD coating has a beneficial effect on K + storage, but the too thick Al 2 O 3 layer oppositely increases the resistivity of K ions. 35 CV analysis was utilized to verify the mechanism of K + intercalation/deintercalation in 20-ALD-NG, 50-ALD-NG, and NG. The scan rate is 1 mV s −1 , and the scan voltage range from 0.01 to 3.00 V. Figure 4A is associated with the intercalation of K + into graphite and the formation of KC 8 .…”