In situ anchoring MnO nanoparticles on self-supported 3D interconnected graphene scroll framework: A fast kinetics boosted ultrahigh-rate anode for Li-ion capacitor

Lithium ion capacitors (LICs) are deemed to be an ideal complement between lithium-ion batteries and supercapacitors. However, the sluggish kinetics that leads to a poor rate capability of Faradaic insertion anodes remains a handicap. Herein, a self-supported architecture is designed by combining an interconnected graphene scroll (GS) framework with in situ formed well-distributed MnO nanoparticles (NPs) for an advanced LIC anode. In this architecture, the inner-connected tubular GS framework plays a multifunctional role: serving as an electron transport bridge like "highways", providing a favorable ion transport pathway as well as accommodating the volume expansion and maintaining the structural stability of MnO. Benefiting from the stable structure, highly localized charge-transfer and low energy diffusion barrier, the as-built anode exhibits an ultrahigh-rate behavior (203 mAh g−1 at 20 A g−1) and robust cycling stability (759 mAh g−1 after 1000 cycles at 2 A g−1). When evaluated as a self-supported anode for LIC, the LIC delivers a high energy density of 179.3 Wh kg−1, a high power density of 11.7 kW kg−1, and a capacity retention of 80.8% after 5000 cycles. Moreover, the corresponding soft-packaged LIC keeps stable electrochemical performances at various bending states. All these features manifest the potential of the architecture for application in advanced energy storage devices.