Surface Modification of Li(Ni0.6Co0.2Mn0.2)O2 Cathode Materials by Nano-Al2O3 to Improve Electrochemical Performance in Lithium-Ion Batteries

Abstract

Al2O3-coated Li(Ni0.6Co0.2Mn0.2)O2 cathode materials were prepared by simple surface modification in water media through a sol-gel process with a dispersant. The crystallinity and surface morphology of the samples were characterized through X-ray diffraction analysis and scanning electron microscopy observation. The Li(Ni0.6Co0.2Mn0.2)O2 cathode material was of a polycrystalline hexagonal structure and agglomerated with particles of approximately 0.3 to 0.8 μm in diameter. The nanosized Al2O3 particles of low concentration (0.06–0.12 wt %) were uniformly coated on the surface of Li(Ni0.6Co0.2Mn0.2)O2. Measurement of electrochemical properties showed that Li(Ni0.6Co0.2Mn0.2)O2 coated with Al2O3 of 0.08 wt % had a high initial discharge capacity of 206.9 mAh/g at a rate of 0.05 C over 3.0–4.5 V and high capacity retention of 94.5% at 0.5 C after 30 cycles (cf. uncoated sample: 206.1 mAh/g and 90.8%, respectively). The rate capability of this material was also improved, i.e., it showed a high discharge capacity of 166.3 mAh/g after 5 cycles at a rate of 2 C, whereas the uncoated sample showed 155.8 mAh/g under the same experimental conditions.

In Situ Surface Modification for Improving the Electrochemical Performance of Ni‐Rich Cathode Materials by Using ZrP2O7

“…[11] Single layer or multilayer coatings are formed on the surface of the material, whichc an transfer electrons or ions and protect the cathode from electrolyte corrosion. [12] Metal oxides or other polyanion materials such as Al 2 O 3 , [13] LaPO 4 , [14] TiP 2 O 7 , [15] Li 4 P 2 O 7 , [16] Li 3 PO 4 /PPy, [17] LiZr 2 (PO 4 ) 3 , [18] Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , [19,20] Al 2 O 3 /LiAlO 2 , [21] and MoS 2 [22] have been reported to be very effective coating materials. Li et al [23] reported Zr modificationh ad dual functions, one is that Zr 4 + can enter into the lattice of the transition metal plane or lithium plane, the other is that the remaining Zr 4 + floats on the surface of particles, formed aL i 2 ZrO 3 coating layer.…”

On the Ageing of High Energy Lithium-Ion Batteries—Comprehensive Electrochemical Diffusivity Studies of Harvested Nickel Manganese Cobalt Electrodes

“…Limitations in the lifetime of lithium-ion batteries still reveal often to be an issue in battery applications as in automotive [8,9,10,11]. In recent years, Lithium Nickel Manganese Cobalt (NMC) for use in positive electrodes eventually offered improved cycle life, thermal stability and energy density capabilities for lithium-ion batteries [12,13,14,15]. Generally, charging and discharging capabilities of electrodes are mainly linked to their lithium ion solid phase diffusion coefficient, which is therefore recognised as a significant kinetic characteristic of Lithium ion intercalation electrode materials [16].…”

Advances and Prospects of Surface Modification on Nickel‐Rich Materials for Lithium‐Ion Batteries†

“…As mentioned before, the coating materials used in Ni‐rich materials include inorganics, organics, and some composite coating materials. For inorganics, the coating materials in recent works mainly include metal oxides (ZnO, [ 33 ] TiO 2 , [ 33‐37 ] Al 2 O 3 , [ 30,33,38‐42 ] ZrO 2 , [ 38,43‐46 ] Nb 2 O 3 , [ 47 ] Co 3 O 4 , [ 33,48 ] Cr 8 O 21 , [ 49 ] MgO, [ 38 ] MnO 2 , [ 50,51 ] V 2 O 3 , [ 33 ] and V 2 O 5 [ 52 ] ), metal fluorides (LiF, [ 53‐55 ] AlF 3 , [ 54,56 ] and FeF 3 [ 57 ] ), metal phosphates (LaPO 4 , [ 58‐60 ] FePO 4 , [ 61‐63 ] CoPO 4 , [ 62,63 ] AlPO 4 , [ 40,62,64‐65 ] and MnPO 4 [ 63,66 ] ), and some kinds of lithium compounds (LiBO 2 , [ 67 ] LiAlO 2 , [ 40,41,68‐71 ] Li 2 MoO 4 , [ 72 ] Li 2 ZrO 3 , [ 43,73‐74 ] Li 3 VO 4 , [ 75‐76 ] Li 3 PO 4 , [ 77‐78 ] Li 2 SiO 3 , [ 79‐81 ] Li 4 SiO 4 , [ 82 ] Li x Ti 2 O 4 , [ 70 ] Li 4 Ti 5 O 12 , [ 83‐84 ] LiZr 2 (PO 4 ) 3 , [ 85 ] and LiAlF 4 [ 54 ] ) and carbon materials (traditional carbon materials, [ 86‐88 ] modified carbon materials, [ 89‐90 ] carbon nanotube materials, […”

“…The coating materials could cover the surface of cathode materials thoroughly due to the introduction of solvent. Sometimes, the precursors of coating materials will even hydrolyze in solvent [ 34,70 ] or react with other substances [ 89,115 ] to form uniform coating layers. The strategies of wet coating methods in Ni‐rich materials include traditional wet coating method (to modify dry coating method [ 103 ] ) and wet chemical coating method (such as sol‐gel method, [ 56,74,116‐118 ] hydrothermal method, [ 41,68 ] and co‐precipitation method.…”