Molecular single-crystal-derived precursor strategy for carbon nanosheets with metal-nitrogen-doping moves towards high capacity lithium ion battery.

[Display omitted] • Expandable single crystal organic precursors to form carbon composites for Li battery. • Carbon nanosheets with nickel-N-doping have high performances in cycle and rate. • Microporous-mesoporous structure formed by metal and N doping enhances Li+ adsorption. • DFT is used to study the adsorption and diffusion of Li+ in the metal-N-doping carbon. Organic-based and metal-organic-based matters are used as electrode materials or precursors for lithium ion batteries because of their high chemical stability and flexible molecular adjustability. Nevertheless, the unobvious electrochemical performance and unclear structure hinder the study of the lithium ions storage mechanism of them. In this paper, we design a well-defined single-crystal structure of organic crystal precursor (CN-Ni/Mn) and derived porous carbon nanosheets with metal-nitrogen-doping (CN-Ni/Mn-800) as electrode materials to construct independent high-performance lithium ion batteries. The study shows that a large number of interconnected micropore mesoporous structures obtained by the transformation of macropores in the materials improve the lithium storage capacity. Density functional theory (DFT) calculations show that the lithium ions adsorption energy and diffusion ability of CN-Ni/Mn-800 are higher than those of N-doped carbon-based materials (CN-800). CN-Ni-800 has the best performance among the anode materials of the half battery. It can deliver stable long-term cycling performance over 1000 charge-discharge cycles at 500 mA g−1. This is a new strategy that designed precursors with a single-crystal structure to derive carbon-based materials for developing high-performance batteries. [ABSTRACT FROM AUTHOR]