Ultrahigh Relative Energy Density and Mass Loading of Carbon Cloth Anodes for K-Ion Batteries

Mass loading and potential plateau are the two most important issues of potassium (K)-ion batteries (KIBs), but they have long been ignored in previous studies. Herein, we report a simple and scalable method to fabricate acidized carbon clothes (A-CC) as high mass loading (13.1 mg cm(-2)) anode for KIBs, which achieved a reversible areal-specific capacity of 1.81 mAh cm(-2) at 0.2 mA cm(-2). Besides, we have proposed the concept of relative energy density to reasonably evaluate the electrochemical performance of the anode. According to our calculation method, the A-CC electrode exhibited an ultrahigh relative energy density of 46 Wh m(-2) in the initial charge process and remained at 40 Wh m(-2) after 50 cycles. Furthermore, we performed the operando Raman spectroscopy (ORS) to investigate the K-ion storage mechanism. We believe that our work might provide a new guideline for the evaluation of anode performance, thereby, opening an avenue for the development of commercial anode.

Automated summary

This study presents a simple and scalable method for fabricating acidized carbon clothes as high mass loading anodes for potassium-ion batteries. The concept of relative energy density was proposed to evaluate the anode performance, with an ultrahigh relative energy density achieved by the A-CC electrode. Additionally, operando Raman spectroscopy was used to investigate the K-ion storage mechanism, providing insights for the development of commercial anodes.