The synergic effect of activated carbon and Li3V1.95Ni0.05(PO4)3/C for the development of high energy and power electrodes

- Bi-material electrode composed by activated carbon and Li3V1.95Ni0.05(PO4)3/C is proposed.
- It is studied as high energy/power positive and negative electrodes, between 3.0-4.3 and 3.0-1.5 V vs. Li/Li+.
- This electrode shows high specific capacity and capacity retention up to 26.6 A g−1.
- Excellent cycle stability is shown over 2000 cycles at 26.6 A g−1.

Exceptionally high specific capacities at ultrahigh charge/discharge currents have been obtained with a bi-material electrode prepared using Li3V1.95Ni0.05(PO4)3/C (LVNP/C) and activated carbon (AC) as coexisting active materials. Thanks to the amphoteric properties of LVNP/C, this electrode designated as LVNP/C-AC, has been evaluated both as positive and negative electrode in 1 M LiPF6 in EC:DMC (1:1). At high specific currents (26.6 A g−1), the bi-material electrode delivers specific capacities as high as 61 and 24 mAh g−1, between 3.0-4.3 V and 3.0-1.5 V vs Li/Li+, respectively. By contrast, the corresponding values for LVNP/C are 49 and 18 mAh g−1. In both potential windows, the bi-material electrode shows an excellent cycling stability over 2000 cycles at 26.6 A g−1, with capacity retention of 95 and 89%, between 3.0-4.3 and 3.0-1.5 V vs Li/Li+, respectively. The synergic effect of the activated carbon on the electrochemical performances of Li3V1.95Ni0.05(PO4)3/C is investigated by comparing the cyclic voltammetry, electrochemical impedance spectroscopy, electronic conductivity, galvanostatic cycling, and scanning electron microscopy of the bi-material electrode with the ones of LVNP/C. This study highlights the huge potentialities of this bi-material electrode for the development of high energy and high power Li-ion hybrid supercapacitors.

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