Extraordinary Ultrahigh‐Capacity and Long Cycle Life Lithium‐Ion Batteries Enabled by Graphitic Carbon Nitride‐Perylene Polyimide Composites

Abstract

Graphitic carbon nitride (g–C3N4) is widely used in organic metal‐ion batteries owing to its high porosity, facile synthesis, stability, and high‐rate performance. However, pristine g–C3N4 nanosheets exhibit poor electrical conductivity, irreversible metal‐ion storage capacity, and short‐term cycling owing to their high concentration of graphitic–N species. Herein, a series of 3,4:9,10‐perylenetetracarboxylic diimide‐coupled g–C3N4 composite anode materials, CN–PIx (x = 0.2, 0.5, 0.75, and 1), was investigated, which exhibited an unusually high surface nitrogen content (23.19–39.92 at.%) and the highest pyridinic–N, pyrrolic–N, and graphitic–N contents reported to date. The CN–PI1 anode delivers an unprecedented and continuously increasing ultrahigh discharging capacity of exceeding 8400 mAh g−1 (1.96 mWh cm−2) at 100 mA g−1 with high specific energy density (Esp) of ∼7700 Wh kg−1 and the volumetric energy density (Ev) of ∼14956 Wh L−1 and an excellent long‐term stability (414 mAh g−1 or 0.579 mWh cm−2 at 1 A g−1). Furthermore, the activation of the CN–PIx electrodes contributes to their superior electrochemical performance, resulting from the fact that the Li+ is not only stored in the CN–PIx composites but also CN–PIx activated the Li0 adlayer on the CN–PI1–Cu heterojunction as an SEI layer to avoid the direct contact of Li0 phase and the electrolyte. The CN–PI1 full cell with LiCoO2 as the cathode delivers a discharge capacity of ∼587 mAh g−1 at a 1 A g−1 after 250 cycles with a Coulombic efficiency nearly 99%. This study provides a strategy to develop N‐doped g–C3N4‐based anode materials for realizing long‐lasting energy storage devices.

Constitutional Isomer-Driven Free Volume Optimization in Polyimide-Based Anodes for Enhanced Capacity and Durability of Li-Ion Batteries

“…The peaks detected at 1380 and 1240 cm –1 were attributed to the vibrational characteristics of the imide C–N bonds. These strong peaks signify the formation of an imide structure within the polymer chain, confirming the successful polymerization of PI. ,,, Furthermore, monomers oriented in different directions were confirmed to exhibit peaks of the same composition in PI, enabling the analysis of variations based on the bonding direction rather than differences in reaction sites. The XPS spectra of PI-L, -B, and -C were investigated to confirm the surface chemical states and composition of various PIs and analyze whether they were different (Figure b–d).…”

Boron-Doped Exfoliated g-C3N4 Nanosheet-Based Phosphors for White Light-Emission and Photocatalytic Degradation

“…All samples show similar FTIR spectra, suggesting that the framework of GCN is well protected during material preparation. As demonstrated, the primary distinctive peaks seen in the range from 900 to 1700 cm –1 were typically attributed to stretching vibration signals of repeating units obtained from aromatic heptazine, consisting of the out-of-plane bending vibrations of the sp 3 C–N bonds and typical sp 2 CN stretching modes, whereas the prominent absorption peak located at roughly 810 cm –1 was responsible for the particular breathing pattern of tri-s-triazine cycles . The absorption band at 883 cm –1 was identified as the mode of N–H deformation in amino groups, while the widened peaks between 3000 and 3500 cm –1 were connected to the stretching vibration of leftover N–H in the bridging C–NH–C units and O–H derived from physically adsorbed water molecules on GCN surface .…”

Linear Polymer Comprising Dual Functionalities with Hierarchical Pores for Lithium Ion Batteries

“…The CVs have significant pseudocapacitive component. In order to understand the mechanism of charge storage, the power law (I=aν b ) was used [48,49] . If the b value extracted from the CVs is close to 1, then the process is predominantly pseudocapacitive.…”

“…In order to understand the mechanism of charge storage, the power law (I = aν b ) was used. [48,49] If the b value extracted from the CVs is close to 1, then the process is predominantly pseudocapacitive. The plot of logν vs log I is linear (Figure 1d).…”