Organic compounds are appealing electrode materials for potassium-ion batteries (PIBs) owing to their economical and eco-friendly nature. Here, we report an important organic semiconductor, 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), as a high-rate anode for PIBs. The PTCDI electrode is found to deliver a high average specific capacity of 310 mA h g⁻¹ at 0.5 A g⁻¹ and a remarkable rate performance (in the range from 0.5 to 5.0 A g⁻¹), which can be attributed to the fast K ion diffusion (up to ∼10⁻⁸ cm² s⁻¹) and low charge-transfer resistance (93 ohm). The proposed six-electron storage mechanism for the PTCDI electrode during the discharge/charge process has been revealed by ex situ infrared (IR) spectroscopy and ex situ X-ray diffraction (XRD), as well as density functional theory (DFT) calculations. This study could pave the way for developing advanced PIB anodes with low cost and high performance.

Batteries based on sulfur cathodes offer a promising energy storage solution due to their potential for high performance, cost-effectiveness, and sustainability. However, commercial viability is challenged by issues such as polysulfide migration, volume changes, uneven phase nucleation, limited ion transport, and sluggish sulfur redox kinetics. Addressing these challenges requires insights into the structural, morphological, and chemical evolution of phases, the associated volume changes and internal stresses, and ion and polysulfide diffusion within the battery. Such insights can only be obtained through real-time reaction monitoring within the battery's operational environment, supported by molecular dynamics simulations and advanced artificial intelligence-driven data analysis. This review provides an overview of in situ/operando techniques for real-time tracking of these processes in sulfur-based batteries and explores the integration of simulations with experimental data to provide a holistic understanding of the critical challenges, enabling advancements in their development and commercial adoption.