Adiponitrile (ADN) has been applied into the lithium ion battery as an additive. However, how the amount of ADN impacts on the cycle and interface property of LiNi0.5Mn1.5O4 is still unknown. In this work, we put different amount of ADN (0.5wt%, 1.0wt%, 2.0wt%, 5.0wt% and 10.0wt%) into the 1 M LiPF6-EC/DMC/EMC (1: 1: 1 by weight) to explore its effect and mechanism. The results of measurements show that the capacity retention of battery with 0.5% ADN has the highest value of 97.1% (126.3 mAh/g) at 0.1C after 50 cycles. While other systems' capacity drops down with the cycles obviously. Especially, when the amount of ADN increases, the polarization becomes serous and there occurs the dark passive film between particles. To explain why this situation happens, we carry out the XPS measurement and analog computation. Combining with these results, we draw a conclusion that as the amount increases, different groups such as (ADN+H) and (ADN-H) are produced and these groups can continue to participate in the film-forming reaction, which is responsible for the poor capacity and passive film. (c) 2019 The Electrochemical Society.