RESUMEN
Lithium-ion battery (LIB) has gained significant recognition for the power cell market owing to its impressive energy density and appealing cost benefit. Among various cathodes, a high-voltage cobalt-poor lithium nickel manganese cobalt oxide cathode (Co-poor NCM cathode) has been considered as a promising strategy to enhance its energy density. Despite these advantages, high-voltage Co-poor NCM cathode-graphite full battery usually suffers from poor rate performance. However, fast charging has been a key indicator for widespread application of power batteries. Although many efforts have been made to improve the charging performance of fresh batteries, few works investigate the charging ability during calendar aging and cycling aging of high-voltage Co-poor NCM cathode-graphite full battery. In this work, we found that the charging ability becomes worse during calendar aging and cycling aging. Results showed that the increasing charge transfer resistance from the cathode is the major obstacle to achieving fast charging during the aging process. To address the problem, high-voltage Al2O3-coated Co-poor NCM cathode successfully prepared via a simple atomic layer deposition (ALD) method has been developed to reduce the decay of charging performance during calendar aging and cycling aging. Al2O3-coated NCM cathode can effectively reduce the growth rate of the resistance of cathode, which is benefiting from the conversion of Al2O3 into LiAlO2 with high ionic conductivity and the restriction formation of rock salt phase. Benefiting from the decreased charge transfer resistance of the NCM cathode, the mismatch of the lithium-ion reaction kinetics is well alleviated, thus effectively reducing the polarization under fast charging. As a result, Al2O3-coated NCM cathode-graphite full battery shows the slow deterioration of charging performance during the aging process. This work provides a promising strategy for constructing fast-charging batteries during calendar aging and cycling aging.
RESUMEN
Layer metal oxides demonstrate great commercial application potential in sodium-ion batteries, while their commercialization is extremely hampered by the unsatisfactory cycling performance caused by the irreversible phase transition and interfacial side reaction. Herein, trimethoxymethylsilane (TMSI) is introduced into electrolytes to construct an advanced cathode/electrolyte interphase by tuning the solvation structure of anions. It is found that due to the stronger interaction between ClO4- and TMSI than that of ClO4- and PC/FEC, the ClO4--TMSI complexes tend to accumulate on the surface of the cathode during the charging process, leading to the formation of a stable cathode/electrolyte interface (CEI). In addition, the Si species with excellent electronic insulation ability are distributed in the TMSI-derived CEI film, which is conducive to inhibiting the continuous side reaction of solvents and the growth of the CEI film. As a result, under a current density of 250 mA g-1, the capacity retention of the NaNi1/3Fe1/3Mn1/3O2 (NFM) cathode after 200 cycles in the TMSI-modified electrolyte is 74.4% in comparison to 51.5% of the bare electrolyte (1 M NaClO4/PC/5% FEC). Moreover, the NFM cathode shows better kinetics, with the specific discharge capacity increasing from 22 to 67 mAh g-1 at 300 mA g-1. It also demonstrates greatly improved rate capability, cycling stability, and Coulombic efficiency under various operating conditions, including high temperature (55 °C) and high cutoff voltage (2.0-4.3 V vs Na+/Na).
