Novel low-cost, high-energy-density (>700 Wh kg−1) Li-rich organic cathodes for Li-ion batteries

For the first time, two novel air-sensitive Li-rich organic cathodes ( m -TP4OLi and p -TP4OLi) are designed and reported. The structure-performance relationship for the two organic cathodes is comparatively studied. Using organic anode of lithium terephthalate (Li 2 TP), the resulting Li 2 TP II p -TP4OLi all-organic Li-ion batteries can deliver the peak discharge capacity of 330 mAh g −1 cathode in 1–3.4 V, corresponding to the high energy density of ~574 Wh kg −1 cathode using the median voltage of 1.74 V. Furthermore, the fabricated graphite II p -TP4OLi Li-ion batteries can show the peak discharge capacity of 305 mAh g −1 cathode in 1.5–3.4 V with a high median voltage of 2.4 V, resulting in the peak energy density of ~732 Wh kg −1 cathode (2.4 V × 305 mAh g −1 ). Meanwhile, the graphite II p -TP4OLi Li-ion batteries exhibit impressive device stability over 20,000 cycles. To the best of our knowledge, the peak energy density of our p -TP4OLi is currently the world record among Li-rich organic cathodes in lab conditions, outperforms the energy density of inorganic LiFePO 4 (~476 Wh kg −1 ), comparable with that of inorganic LiCoO 2 (~760 Wh kg -1 ) under the same lab conditions.