Lithium-ion batteries are used in many portable electronic devices. However, lithium resources are limited and finding other materials for batteries would, thus, be useful. Potassium could be a low-cost alternative, but suitable electrode materials are still needed. Organic cathodes are promising for potassium-ion batteries (PIBs), but so far, their rate performance and stability are not satisfactory.

Bingan Lu and colleagues, Hunan University, Changsha, China, have developed an ultrafast and highly stable potassium–organic battery, using a highly conductive organic cathode in combination with an optimized electrolyte. The team used annealed perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) as the organic cathode and potassium bis(fluoroslufonyl)imide (KFSI) in 1,2-dimethoxyethane (DME) as the electrolyte.

The resulting potassium–organic battery achieves a high power density of 9796 W kg⁻¹, an energy efficiency of 89 %, and is stable for 1,000 charge/discharge cycles. The researchers attribute this performance to the higher electric conductivity and improved potassium-ion transport of annealed PTCDA compared with other organic electrode materials.

• An Ultrafast and Highly Stable Potassium-Organic Battery,
  Ling Fan, Ruifang Ma, Jue Wang, Hongguan Yang, Bingan Lu,
  Adv. Mater. 2018.
  https://doi.org/10.1002/adma.201805486