▎ 摘　　要

NOVELTY - A transition metal selenium-sulfur complex comprises a metal selenium-based composition (I) and having a heterojunction structure formed by uniformly dispersing amorphous carbon-coated particles on the surface of the reduced graphene oxide. USE - Transition metal selenium-sulfur complex is for forming negative electrode of sodium ion battery. ADVANTAGE - The transition metal selenium-sulfur complex-based electrode provides sodium ion battery having excellent rate performance and cycle stability. DETAILED DESCRIPTION - A transition metal selenium-sulfur complex comprises a metal selenium-based composition of formula: (1-w)AnSm/wAxSey/rGO (I), where A is Zn, Co, Sn or Fe, w is 0-1 (excluding 0 and 1) and AnSm is cobalt sulfide and AxSey is cobalt selenide. The AnSm phase and AxSey phase forming heterojunction structure by uniformly dispersing amorphous carbon-coated particles on the surface of the reduced graphene oxide. An INDEPENDENT CLAIM is included for preparation of transition metal selenium-sulfur complex, which involves reacting 2-methylimidazole with salt comprising element (A), subjecting to heat treatment to form precursor, mixing the precursor with graphene oxide to make the precursor adhere to the surface of graphene oxide and adding selenium source and sulfur source to carry out hydrothermal reaction.