Janus from the synchronous construction of CN network and P-π conjugation: Inhibiting volume expansion and promoting lithium-ion battery performance of ZnSe

Abstract

High-capacity lithium anode materials are very important for the development of lithium storage. However, the volume expansion and electron transport during charging and discharging hinder the development of high capacity and longevity. Herein, the three-dimensional P-π conjugate and nitrogen-doped carbon (CN) network framework was synchronously constructed by a simple and practical double construction strategy to solve the problems of volume expansion and electron transport. The experimental results indicate that the successfully synthesized transition metal zinc selenide (ZnSe) composites material possesses excellent electrochemical properties: an initial reversible capacity is capacity of 1211.8 mAh/g, and the reversible discharge capacity remains at 936.4 mAh/g after 300 cycles (at 1 A/g current density). It is much better than that of pure ZnSe. The enhanced electrochemical performances of the anode can be attributed to its high surface area and abundant mesopores constracted by the 3D CN network framework. Furthermore, the P-π conjugation reduces the system energy and thus accelerates the electron transport. These characteristics provide numerous pathways and sites for Li+ transfer and storage, thus contributing to the pseudo-capacitance capacity. The present work may provide new ideas and strategies for the solution of electrode material expansion and electron transport problems.