A high performance lithium ion capacitor achieved by the integration of a Sn-C anode and a biomass-derived...

Hybridizing battery and capacitor materials to construct lithium ion capacitors (LICs) has been regarded as a promising avenue to bridge the gap between high-energy lithium ion batteries and high-power supercapacitors. One of the key difficulties in developing advanced LICs is the imbalance in the power capability and charge storage capacity between anode and cathode. Herein, we design a new LIC system by integrating a rationally designed Sn-C anode with a biomass-derived activated carbon cathode. The Sn-C nanocomposite obtained by a facile confined growth strategy possesses multiple structural merits including well-confined Sn nanoparticles, homogeneous distribution and interconnected carbon framework with ultra-high N doping level, synergically enabling the fabricated anode with high Li storage capacity and excellent rate capability. A new type of biomass-derived activated carbon featuring both high surface area and high carbon purity is also prepared to achieve high capacity for cathode. The assembled LIC (Sn-C//PAC) device delivers high energy densities of 195.7 Wh kg^-1 and 84.6 Wh kg^-1 at power densities of 731.25 W kg^-1 and 24375 W kg^-1, respectively. This work offers a new strategy for designing high-performance hybrid system by tailoring the nanostructures of Li insertion anode and ion adsorption cathode.