Cable-like heterogeneous porous carbon fibers with ultrahigh-rate capability and long cycle life for fast charging lithium-ion storage devices†
In this paper, we propose a space-confined foaming approach to fabricate cable-like heterogeneous porous carbon fibers (Si-CPCFs) containing an inner graphitized carbon “conductor” and an outer Si-doping amorphous carbon “shield”. Benefiting from the fast Li+ intercalation and high conductivity of the “inner conductor”, and the rich pseudocapacitance of the “outer shield”, the Si-CPCFs exhibit an ultrahigh-rate capability and cycling performance, leading to a high capacity of 132 mA h g−1 even at an ultra-high current density of 100 A g−1 after 10 000 cycles. The assembled lithium ion hybrid supercapacitors (LIHCs) also deliver a superior energy density of 50 W h kg−1 at an ultra-high power density of 113 kW kg−1, really achieving both a high energy density and power density of LIHCs. The success of the cable-like heterogeneous porous carbon architecture proposes a new direction to circumvent the discrepancy in kinetics and capacity mismatch, and also attracts more attention to heterogeneous nanostructures with multiple functions.