Curved Nanographene-Graphite Hybrid Anodes with Sequential Li plus Insertion for Fast-Charging and Long-Life Li-Ion Batteries

Abstract

Graphite remains the most widely used anode material for lithium-ion batteries (LIBs). However, improvements are essential to meet the demand for high-performance anodes in full-cell configurations. Here, the synergistic electrochemical performance of a curved nanographene-graphite hybrid anode composed of mesocarbon microbeads (MCMB) is investigated, and Cl-substituted contorted hexabenzocoronene (Cl-cHBC), designed to improve the specific capacity, rate capability, and cycling stability. The optimized 1:1 blend forms a homogeneous morphology, in which sphere-like MCMB particles are uniformly embedded within needle-like Cl-cHBC crystals without macrophase separation. This architecture enables sequential Li-ion insertion and leads to a synergistic improvement in the electrochemical performance. In a half-cell, the hybrid anode achieves 100 mAh g-1 at 4 A g-1, outperforming the pristine MCMB graphite (approximate to 20 mAh g-1 at 4 A g-1). In full-cells paired with a single-crystal LiNi1-y-zCoyMnzO2811 cathode, it shows exceptional rate capability (approximate to 100 mAh g-1 at 5 C) and stability (70% capacity retention after 1000 cycles at 5 C). Furthermore, a pouch cell incorporating the hybrid anode delivers 115 mAh g-1 at 1 C and stable performance over 2100 cycles with a Coulombic efficiency of 99%. These results demonstrate the practical potential of sequential Li-ion insertion into Cl-cHBC/MCMB composites for high-performance LIB applications.