Porous N-doped carbon nanostructure integrated with mesh current collector for Li-ion based energy storage

A self-assembled mesoporous silica sphere templating process was developed to create hierarchical continuous porous coral reef like N-doped carbon nanostructures on stainless steel meshes as bifunctional electrodes for ultrahigh performance lithium ion based energy storage devices. The coral reef like carbon nanostructure achieved a high specific surface area of 1229 m(2) g(-1) and a large specific pore volume of 2.21 cm(3) g(-1), without application of chemical activations. The electrode, when serving as an anode for lithium ion batteries (LIB) or lithium ion capacitors (LIC), delivered an ultrahigh specific capacity of 2058 mAh g(-1) at 0.2 A g(-1). If used as a cathode for LICs, it generated a high specific capacity of 125 mAh g(-1) at 0.1 A g(-1). The LICs assembled from using the electrode as both the cathode and anode, exhibited a high energy density of 145 Wh kg(-1) at a power density of 1.4 kW kg(-1) and maintained an energy density of 58 Wh kg(-1) under an ultrahigh power density of 27.3 kW kg(-1), among the top tie of the state-of-the-art LICs. The cycling stability of the LIC was outstanding with a 85% capacity retention after 5000 cycle operations at 5 A g(-1). The hierarchical continuous porous coral reef like N-doped carbonaceous nanostructure provides micropores as micro-reservoirs of Li ions for local and fast Li ion intercalation/de-intercalation, edge N-doping for additional redox pseudo-capacitances, and large pore volumes to accommodate the volume expansion/shrinkage at the charge/discharge cycles and to offer fast mass transfer path for electrolyte ions, altogether leading to the successful applications as bifunctional electrodes for Li ion based energy storage devices.