Ultrahigh Capacity Retention of a Li₂ZrO₃-Coated Ni-Rich LiNi_0.8Co_0.1Mn_0.1O₂ Cathode Material through Covalent Interfacial Engineering

Abstract

Nickel-rich LiNi0.8Co0.1Mn0.1O2 (LNCM811) is a promising lithium-ion battery cathode material, whereas the surface-sensitive issues (i.e., side reaction and oxygen loss) occurring on LNCM811 particles significantly degrade their electrochemical capacity retentions. A Li2ZrO3 coating layer can mitigate the problem by preventing these interfacial issues. However, the capacity retentions still need improvement. The normally used sol–gel coating method relies on weak hydrogen-bonding interaction between coating species (i.e., hydrated ZrO2) and cathode particles that discourages effective coating layers. Herein, we present a covalent interfacial engineering for the uniform Li2ZrO3 coating on LNCM811 materials. Experiments and density functional theory calculations indicate that the strong covalent interactions between citric acid and the Ni0.8Co0.1Mn0.1(OH)2 (NCM811) precursor effectively promote the adsorption of ZrO2 coating species on the NCM811 precursor, which is eventually converted to uniform Li2ZrO3 coating layers of about 7 nm after thermal annealing. The uniform Li2ZrO3 coating endows LNCM811 cathode materials with an exceptionally high capacity retention of 98.7% after 300 cycles at 1 C. This work shows the great potential of covalent interfacial engineering for improving the electrochemical cycling capability of Ni-rich lithium-ion battery cathode materials.

Structural Reinforcement through High-Valence Nb Doping to Boost the Cycling Stability of Co-Free and Ni-Rich LiNi0.9Mn0.1O2 Cathode Materials

“…All analytical grade chemicals were used without further purification. The precursor Ni 0.9 Mn 0.1 (OH) 2 was synthesized using a similar co-precipitation method described in our previous work. − A solution of NiSO 4 ·6H 2 O and MnSO 4 ·H 2 O was prepared in a 9:1 molar ratio with a total metal ion concentration of 2 M. A continuously stirred glass vessel (5 L) was heated to 60 °C using a water bath and filled with 50 mL of ammonia solution (9.6 M) diluted with 450 mL of water. The glass vessel was purged with nitrogen gas to remove the air.…”

“…The family of oxides LiNi x Co y Mn z O 2 (NCM, x + y + z = 1) − inherits the layered structure of LiCoO 2 and has found widespread use as cathode materials for lithium-ion batteries in various electrical devices, including 3 C products and electric vehicles. Using Ni-rich ( x ≥ 0.8) layered oxides and those with even higher Ni content (e.g.…”

Structural Stabilization of Cation-Disordered Rock-Salt Cathode Materials: Coupling between a High-Ratio Inactive Ti4+ Cation and a Mn2+/Mn4+ Two-Electron Redox Pair

“…Rechargeable lithium-ion batteries have now been applied successfully in portable electronic devices and promoted the rapid development of smart grid and electric vehicles. − These fast-developing fields further place growing demands for higher energy density of lithium-ion batteries. Over the past decade, research on lithium-ion battery cathodes has been largely dominated by ordered Ni-rich and Li-rich layered cathode materials.…”

Phosphorus-Containing C9H21P3O6 Molecules as an Electrolyte Additive Improves LiNi0.8Co0.1Mn0.1O2/Graphite Batteries Working in High/Low-Temperature Conditions

“…Generally, the effective strategy for surface modification of NCM 811, such as nanoscale coating and function coating, have been to form a protective barrier at the electrolyte interface. There are currently three main functional coatings: electrochemically inactive coating, − Li conductive coating − and conducting-polymer coating. − However, complicated synthesis processes and high cost restrict their widespread application. Therefore, it is significant to optimize the electrolyte system to achieve high energy density and long cycle stability for LIBs.…”