Graphene‐Functionalised Olivine Lithium Manganese Phosphate Derivatives for High Performance Lithium‐ion Capacitors

Lithium manganese phosphate nanoparticles (LiMnPO4; LMP) as well as the nickel-doped (LMNP) and graphenised derivatives (G-LMNP) were synthesized. Electrochemical characteristics of the materials were examined using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge. Lithium ion capacitors (LIC) fabricated using LMP and composite materials as positive electrodes and activated carbon as the negative electrode, exhibited a specific capacitance of 60 F g(-1)at a current load of 0.1 A g(-1)for the AC//G-LMNP LIC. Capacitance retention of 83 % was obtained by the AC//G-LMNP LIC after 750 cycles, with a high specific power of 19 kW kg(-1)at 0.5 A g(-1).