Study On The Effect Of Alumina Ceramic Coating On The Performance Of Lithium Ion Battery

ABSTRACT:There are many factors affecting the safety performance of lithium ion battery,and safety performance is the key to restrict the large-scale development of lithium ion batteries. The ceramic coating is one way to improve the electrochemical performance and the safety performance of the battery, for its excellent electrolyte infiltration and high temperature resistant performance.This article based on the lithium ion battery electrode, study ceramic coating on low cost and good compatibility with the battery, the purpose is to improve the electrochemical performance and the safety performance of lithium ion battery.In this paper, based on the literature review, optimization of industrial raw material nano alumina ceramic raw material, studied the effect of nano alumina properties and kinds of binder ratio of ceramic coating, the compatibility of ceramic coating and graphite anode and effects on the battery performance and safety performance. The cyclic voltammetry (CV), AC impedance (EIS), constant current charge discharge and scanning electron microscopy (SEM), X ray diffraction (XRD) and a series of test methods of characterization, physical and chemical properties of ceramic coating and its effect on the cell performance, the main results as follows:1) Nano alumina particle dispersion properties directly affect the uniformity of ceramic coating. The small particle size, uniform dispersion of alumina can effectively prevent slurry reunion, oil coating and water in graphite anode have the best compatibility. The ceramic coating own nanometer pore after high temperature drying ceramic,which is benefit for the electrolyte infiltration and absorption.2)The ratio of Alumina particles and binder in ceramic coating has an important effect on the performance of battery. Comparison of alumina particles with the polymer binder ratio of9:1(AG-T1) and8:2(AG-T2), the first charge discharge efficiency for AG-T1is83.3%, the ordinary graphite anode is82.9%, and AG-T2is80.4%. Button cell cycle results show that, T1can improve the cycle performance of battery, T2reduces the cycle performance of battery. Button type battery AC impedance spectroscopy and cyclic voltammetry results show that ceramic coating T1is compatible with anode well.3) Absorbing and retaining liquid rate test showed that, the ceramic coating is beneficial to the electrolyte absorption and preservation. After anode coated ceramic coating, the battery capacity retention rate at88.6%for500cycles, while the ordinary battery capacity retention rate is85.3%. Ceramic coatings also increased cell rate performance and low temperature perormance in a certain extent. In short, acupuncture, extrusion, the impact of heavy and hot box safety experiment, the ceramic coating cells were not thermal runaway, while in acupuncture, impact of heavy and hot box test, the ordinary cells were fire explosion. The results indicated that the ceramic coatings can improve the safety performance of the battery. Ceramic coatings battery in good safety performance remained after300cycles of the battery, but not after500cycles of safety test. The negative electrode sheet electron microscope show that, the ceramic coating were disbanding after500cycles, which is the main reason for the performance degradation caused by security.