Controllable TiO₂ coating on the nickel-rich layered cathode through TiCl₄ hydrolysis via fluidized bed chemical vapor deposition

Abstract

Surface coating of metal oxides is an effective approach for enhancing the capacity retention of a nickel-rich layered cathode.

Actual pseudocapacity for Li ion storage in tunable core‐shell electrode architectures

“…During the solvothermal reaction, P123, ethylene glycol and ethanol serves the purpose of co‐surfactant, while P123 play the role of a reducing agent to reduce Ni(CH 3 COO) 2 to nickel and etches the NF surface for the growth of Ni‐OH precursor 46 . In addition, HCl is formed upon decomposition TiCl 4 that further hasten the reduction of nickel and etching of the internal 3D structure of the NF 47,48 . The Ti‐doped Ni‐OH precursor was oxidized to obtain Ti‐doped NiO (denoted NFNTO).…”

“…46 In addition, HCl is formed upon decomposition TiCl 4 that further hasten the reduction of nickel and etching of the internal 3D structure of the NF. 47,48 The Ti-doped Ni-OH precursor was oxidized to obtain Ti-doped NiO (denoted NFNTO). Meanwhile, series of controlled sample were also synthesized for detailed synthetic mechanism.…”

Sr-Based Sub/Surface Integrated Layer and Bulk Doping to Enhance High-Voltage Cycling of a Ni-Rich Cathode Material

“…The popularity of consumer electronics and the rapid development of electric vehicles have put forward higher energy density and longer service life requirements for lithium-ion batteries (LIBs), which are mainly limited by cathode materials. − Among the various promising cathode materials, the nickel-rich layered oxides (LiNi x Co y Mn z O 2 , x ≥ 0.6, x + y + z = 1) attract widespread attention due to their extremely high reversible capacity that can even exceed 200 mAh g –1 when the charging voltage exceeds 4.5 V. Except for the contribution of cations, additional capacity is achieved by the redox reaction of anionic oxygen (O 2– /O 2 n – , where 1 < n < 2) during a high charging voltage. , However, Ni-rich materials suffer from severe phase transformation and surface side reactions that cause the capacity and voltage to fade during high-voltage cycling. − Therefore, many surface protectors, such as oxides (e.g., Al 2 O 3 , ZrO 2 , TiO 2 ), − phosphates (Li 3 PO 4 , FePO 4 , LiFePO 4 ), − and fluorides (AlF 3 , LiF, MgF 2 ), − were designed to mechanically restrain unwanted structural transformations and inhibit surface side reactions by avoiding direct contact between the cathode materials and the electrolyte.…”

Electrochemical Performance and Elevated Temperature Properties of the TiO2-Coated Li[Ni0.8Co0.1Mn0.1]O2 Cathode Material for High-Safety Li-Ion Batteries

“…10 To be effective, the coating material should (i) not alter the crystal structural of the cathode material, (ii) be thin enough and well-dispersed not to reduce the electrical conductivity, and (iii) prevent degradation of the cathode material. 9,10, 21,22 Table 1 summarizes the electrochemical performance of some surface-modified NCM811 cathode materials at elevated temperatures. 23−30 Among the various materials, TiO 2 has been used as the coating for different cathode materials including NCM523, 31 NCM622, 32 LiMn O 4 , 33 LiNi 0.5 Mn 1.5 O 4 , 34 and LiFePO 4 35 owing to its nontoxic nature, low cost, and thermal/chemical stability.…”

“…It is believed that the coating strategy is more effective than doping in providing a stable cathode–electrolyte interface and suppressing unwanted side reactions . To be effective, the coating material should (i) not alter the crystal structural of the cathode material, (ii) be thin enough and well-dispersed not to reduce the electrical conductivity, and (iii) prevent degradation of the cathode material. ,,, Table summarizes the electrochemical performance of some surface-modified NCM811 cathode materials at elevated temperatures. − Among the various materials, TiO 2 has been used as the coating for different cathode materials including NCM523, NCM622, LiMn 2 O 4 , LiNi 0.5 Mn 1.5 O 4 , and LiFePO 4 owing to its nontoxic nature, low cost, and thermal/chemical stability . Mo et al studied the TiO 2 -coated LiNi 0.6 Co 0.2 Al 0.2 O 2 cathode materials and reported that the presence of TiO 2 coating minimizes the undesired side reaction and stabilizes the structure of NCM622 during charge–discharge cycles.…”