Transient High-Power Output of Aprotic Li-O 2 Batteries Based on Cathode Capacitance Behavior

Abstract

© 2018 The Electrochemical Society. Due to the sluggish oxygen reduction reaction (ORR) process of an O2cathode, the power delivery of aprotic Li-O2batteries (A-LOBs) is widely considered to be very poor. However, this work demonstrates the transient high-power output of A-LOBs based on the capacitive feature of the O2cathode, including the intrinsic capacitance of cathode material and the ORR pseudocapacitance of the absorbed O2on the cathode surface, by using graphene with high specific surface area. The O2cathode delivers a high specific power of 12 026 W kggraphene−1while also providing a large specific energy of 1216 Wh kggraphene−1. Pulse-discharge tests show that A-LOBs can achieve the transient high power output at high current via the “capacitor-type”, while maintaining the high energy output at low current due to the “battery-type” (ORR). This work indicates that A-LOBs can deliver both high energy density and high transient power, which may be an appeal for the next-generation electric vehicles.