Molten‐Salt‐Assisted Conversion of Waste Soybean Cake Into High‐Performance N and O Co‐Doped Porous Carbon for Lithium‐Ion Battery Anodes

In this article, an efficient method for converting waste soybean cake powder into N, O co‐doped porous carbons based on molten‐salt‐assisted pyrolysis strategy is reported, and its electrochemical performance as anode for lithium‐ion batteries (LIBs) is systematically investigated. Results show that the pyrolysis temperature (500°C–700°C) significantly affected the lithium storage behavior by regulating the pore structure, surface chemistry, and orderliness of carbon materials. Among them, the pyrolysis product at 600°C shows the best comprehensive performance. This is due to the abundant active sites provided by its hierarchical pores, the in situ doped N and O atoms enhance the conductivity of the electrode, and the three‐dimensional carbon skeleton effectively buffers the volume expansion. Therefore, C‐600 exhibits a high specific capacity of 563.3 mAh g −1 at 0.1 A g −1 , and the capacity increases to 641.2 mAh g −1 after 200 cycles. Furthermore, it still maintains 398.8 mAh g −1 after 500 cycles at 1 A g −1 . The Li + diffusion coefficient reaches to 1.07 × 10 −11 cm 2 s −1 , which is significantly higher than that of traditional biomass carbon. Therefore, this work provides a new idea for designing high‐performance and sustainable anode materials for LIBs.