Organic electrode for non-aqueous potassium-ion batteries

•For the first time, we designed and fabricated a non-aqueous potassium-ion batteries (KIBs) by PTCDA as the cathode.•The PTCDA exhibits a high capacity of 131 mA h g−1 in the potential range of 1.5–3.5 V vs. K/K+.•PTCDA shows great capacity retention of 66.1% over 200 cycles.•K11PTCDA can be obtained when discharging PTCDA to low voltage.

Potassium-ion (K-ion) batteries can be an attractive alternative for grid-scale energy storage due to the abundance of K resources. For the first time, we designed and fabricated a non-aqueous K-ion battery (KIB) by employing 3,4,9,10-perylene–tetracarboxylicacid–dianhydride (PTCDA) as the cathode. The PTCDA electrode exhibits a high capacity of 131 mA h g−1 in the potential range of 1.5–3.5 V vs. K/K+, which corresponds to the insertion of two K ions per PTCDA molecule. The PTCDA cathode also shows great cycling performance, with a capacity retention of 66.1% over 200 cycles. Furthermore, K11PTCDA can be obtained when discharging PTCDA to 0.01 V vs. K/K+, which delivers a high capacity of 753 mA h g−1. The excellent electrochemical performance makes PTCDA a promising organic electrode based on K-ion chemistry for grid-scale energy storage.

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