▎ 摘　　要

NOVELTY - A secondary-ion battery comprises positive electrode, negative electrode, electrolyte and separator. The positive and negative electrodes are connected to the separator. The positive electrode is composite sheet comprising layer (A) of nickel-titanium alloy and grapheme layer (B). The negative electrode is aluminum-manganese alloy containing 3-8 %mass manganese. The electrolyte comprises trivalent aluminum ion, chloride ion and 1-ethyl-3-methylimidazolium ion. The molar ratio of 1-ethyl-3-methylimidazolium ion and trivalent aluminum ion is more than 3:2 and less than 4:1. USE - Secondary-ion battery (claimed). ADVANTAGE - The secondary-ion battery is safe, and has energy density of 90 Wh/Kg or more, excellent thermal stability and cycle characteristics, and does not explode. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of secondary-ion battery.