context: Compounds derived from hexaazatriphenylene (HAT) might reversibly accept up to six electrons per HAT unit and have excellent cycling capabilities. They might withstand 10000–50000 cycles with small capacity fading. Kapaev et al. showed that HAT-based polymer P14 delivered a Qm of up to 245 mA h g−1 at 50 mA g−1 in a 0.9–3.4 V vs. K potential range. Interestingly, the reversible capacity continuously increased upon cycling at 10 A g−1 from 150 to 169 mA h g−1 after 4600 cycles. This slow activation, of which the reasons are yet unknown, makes P14 the most stable among all reported cathode materials for non-aqueous K-based batteries. After 4600 cycles, the cells short-circuited due to dendrite formation at the potassium anode.
answer: P14 