Recent advances and perspectives on prelithiation strategies for lithium-ion capacitors

Lithium-ion capacitors (LICs), consisting of a capacitor-type material and a battery-type material together with organic electrolytes, are the state-of-the-art electrochemical energy storage devices compared with supercapacitors and batteries. Owing to their unique characteristics, LICs received a lot of attentions, and great progresses have been achieved, especially in the exploration of cathode and anode materials. Prelithiation techniques are regarded as indispensable procedures for LICs systems, which can compensate for the initial irreversible capacity loss, increase the Li + concentration in the electrolyte, raise the working voltage and resolve the safety and cycle stability issues; however, its research progress is slow, and there is not enough attention until now. In this overview, we look into the ongoing processes on the recent development of prelithiation technologies, especially in organic electrolyte consumption-type LICs. In particular, some prelithiation strategies for LICs are summarized and discussed in detail, including the ex situ electrochemical method, in situ electrochemical method, and cathode prelithiation additives method. Moreover, we propose some unresolved challenges and prospects for prelithiation technologies from the basic research ideas and future key research directions. This work aims to bring up new insights to reassess the significance of premetallation strategies for advanced hybrid-ion capacitors based on the currently proposed prelithiation strategies. Graphical abstract