Graphitic carbon nitride-derived high lithium storage capacity graphite material with regular layer structure and the structural evolution mechanism

作者：Yuan, Zhipeng; Hu, Zhuang; Gao, Peng; Zhang, Weihua; Tang, Yu; Li, Lingfang; Shi, Kui; Han, Shaochang; Fan, Changling^*; Liu, Jinshui^*; Liu, Jilei

来源：Electrochimica Acta, 2022, 409: 139985.

DOI：10.1016/j.electacta.2022.139985

• Lithium-ion batteries
• Graphitic carbon nitride
• Graphite anode
• Denitrification
• Catalytic graphitization

A novel graphite anode (Ni-g-C3N4) is synthesized by using graphitic carbon nitride as the precursor and nickel (Ni) as the catalyst, which dramatically decreases the reaction temperature to 850 degrees C. The critical role of Ni in denitrifying g-C3N4 to produce high-quality graphite is identified, with the results showing that the nitrogen content decreases from 62.1% to 1.2% and thus leading to greatly enhanced electrical conductivity as well as excellent rate capability, cycle performance and structure integrity. The Ni-g-C3N4 exhibits typical low voltage plateau characteristic of graphite anode and the transformation of graphite intercalation compounds are investigated in the in-situ XRD analysis during the discharge/charge process. The capacity retention is as high as 99.3% after 600 cycles at 0.5 A.g(-1), demonstrating excellent structural stability. Moreover, the evolution from g-C3N4 to graphite Ni-g-C3N4 is investigated via TG-MS and hightemperature in-situ XRD, which clearly reveals that the catalytic graphitization processes mainly consist of the dissolution, re-precipitation and carbide conversion, along with the formation of intermediate Ni3C and the release of nitrogen gas. In general, this work not only proposes a novel method to synthesize high performance graphite anode from g-C3N4 for lithium ion batteries, but also unravels the catalytic graphitization mechanism.