An ultrafast battery performing as a supercapacitor: Electrode tuning for high power performance

Abstract

In this work we present an ultrafast battery (UFB) based on olive pit derived hard carbon (HC) and LiNi1/3Mn1/3Co1/3O2 (NMC111). In view of the faradaic nature of the active materials, the system should be catalogued as a battery. Nevertheless, the quadratic shape of the voltammograms demonstrates that the system can mimic supercapacitor performance, being able to respond to peak power demands in few seconds. Electrode engineering, by merely tailoring mass loading and mass balance, enabled such duality. On the one hand, at an operating voltage window of 2.9–3.75 V, the system is able to deliver 212 Wh·cm−3 at 1000 W·cm−3 (respect to the active mass) within a discharge time of 10 min. On the other hand, the system can deliver 87 Wh·cm−3 at 6000 W·cm−3 within a discharge time of 32 s. In addition, the system shows capacity retention over 90% after 30 000 cycles at a current density of 1 A·g−1 (tdischarge = 32 s). This innovative design covers the existing gap between batteries and supercapacitors, resulting in an astonishing energy-to-power device that can rule out the electrochemical energy device scene.