A Graphene-like Oxygenated Carbon Nitride Material for Improved Cycle-Life Lithium/Sulfur Batteries

Abstract

Novel sulfur (S) anchoring materials and the corresponding mechanisms for suppressing capacity fading are urgently needed to advance the performance of Li/S batteries. Here, we designed and synthesized a graphene-like oxygenated carbon nitride (OCN) host material that contains tens of micrometer scaled two-dimensional (2D) rippled sheets, micromesopores, and oxygen heteroatoms. N content can reach as high as 20.49 wt %. A sustainable approach of one-step self-supporting solid-state pyrolysis (OSSP) was developed for the low-cost and large-scale production of OCN. The urea in solid sources not only provides self-supporting atmospheres but also produces graphitic carbon nitride (g-C3N4) working as 2D layered templates. The S/OCN cathode can deliver a high specific capacity of 1407.6 mA h g(-1) at C/20 rate with 84% S utilization and retain improved reversible capacity during long-term cycles at high current density. The increasing micropores, graphitic N, ether, and carboxylic O at the large sized OCN sheet favor S utilization and trapping for polysulfides.

An integrally-designed, flexible polysulfide host for high-performance lithium-sulfur batteries with stabilized lithium-metal anode

“…The ACNF@MnO 2 electrode without CNT suffers from poor rate capability due to slow electron and ion transport ( Figure S8). Figure S9) [42,43]. The discharge plateaus correspond to the reduction of elemental sulfur to high-order polysulfides and then to Li 2 S/Li 2 S 2 , while the charge plateaus represent the reverse process ( Figure S10) [44].…”

Structural Design of Lithium–Sulfur Batteries: From Fundamental Research to Practical Application

“…The design of multi-architectural and multi-functional cathode materials has the potential to overcome these challenges and has been one of the most researched strategies in recent years. Currently, physical routes including capillary force absorption [14,[51][52][53][54][55][56][57], shell coating [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75], and chemical routes containing heteroatom-doped carbons [76][77][78][79][80][81][82][83][84][85][86][87][88][89][90] and metal-based additives [91][92][93][94][95][96][97][98][99]…”

Polar Ultrathin Self‐Doping Carbon Nitride Nanosheets with Intrinsic Polysulfide Adsorption for High Performance Lithium‐Sulfur Batteries

“…[18] Furthermore, the cycled CÀCNN/S sample was collected by disassembling the cycled LiÀS battery cell and characterized by XPS. As shown in Figure 10 c, the N 1s XPS of the CÀCNN/S before cycling was resolved to three main peaks at 398.7 eV for pyridinic N, 399.7 eV for pyrrolic N, and 401.1 eV for graphitic N. [48,49] After cycling, the peaks at 398.7 eV and 399.7 eV shifted to 399.3 eV and 399.9 eV, while the peak at 401.1 eV was almost invariable (Figure 10 e), further indicating the existence of chemical interaction between LiPS and pyridinic, pyrrolic nitrogen. The post-mortem SEM image in Figure S9 revealed that some lithium polysulfides particles were adsorbed and deposited on the surface of CÀCNN after long cycling, which further confirmed the strong chemical interactions between CÀCNN and LiPS.…”