Construction of pseudocapacitive Li2-xLaxZnTi3O8 anode for fast and super-stable lithium storage

Abstract Lithium-ion capacitors (LICs) composed of battery-type anodes with large energy densities and capacitor-type cathodes with high power densities are considered as appealing energy-storage devices. Here, a LIC with good performance is constructed using active carbon (AC) as the cathode and Li1.95La0.05ZnTi3O8 (LL5ZTO) as the anode. LL5ZTO doped with La is synthesized via a one-step solid-state route. The kinetics and structural stability of LZTO are enhanced by La-doping. Thus, LL5ZTO exhibits good Li-storage performance. The discharge specific capacity reaches 182.6 mAh g−1 at 3 A g−1 (120th cycle) for LL5ZTO. The LIC based on the LL5ZTO anode and the AC cathode delivers an energy density of 59.72 Wh kg−1 at 846.4 W kg−1, and a high power density of 8771 W kg−1 at 19.49 Wh kg−1. Furthermore, the capacity retention is over 90% after 3000 cycles for the LIC at 2 A g−1. The good electrochemical performance indicates that the constructed LIC is expected to use in advanced energy storage devices.