An Ion-Pumping Interphase on Graphdiyne/Graphite Heterojunction for Fast-Charging Lithium-Ion Batteries

The sluggish lithium-ion (Li-ion) transport kinetics in graphite anode hinders its application in fast-charging Li-ion batteries (LIBs). Here, we develop an ion pumping interphase (IPI) on graphdiyne (GDY)/ graphite heterojunction anodes to boost the ionic transport kinetics and enable high-performance, fast-charging LIBs. The IPI changed the ion solvation/desolvation environment by covalent/non-covalent interactions with Li ions or solvents to optimize solid-electrolyte interphase (SEI) and regulate Li-ion transport behavior. We studied the in situ growth of few-layer GDY on graphite surface (GDY/graphite) as the IPI and found that the strong interaction between GDY and Li ions enabled surface-induced modification of the ion solvation behavior and surface-assisted desolvation effect to accelerate the Li-ion desolvation process. A functional anion-derived SEI layer with improved Li-ion conductivity was created. Together with the generated built-in electric field at GDY/ graphite hetero-interface self-pumping Li ions to intercalate into the graphite, the Li-ion transport kinetics was significantly enhanced to effectively eliminate Li plating and large voltage polarization of the graphite anodes. A fast Li intercalation in GDY/graphitewithout Li oversaturation at the edge of the graphite was directly observed. The superior performance with high capacity (139.2 mA h g-1) and long lifespan (1650 cycles) under extremely fast-charging conditions (20 C, 1 C = 372 mA g-1) was achieved on GDY/ graphite anodes. Even at low temperatures (-20 degrees C), a specific capacity of 128.4 mA h g-1 was achieved with a capacity retention of 80% after 500 cycles at a 2 C rate.