A solid electrolyte material according to the present disclosure is represented by the following composition formula (1), Li.sub.aAl.sub.bO.sub.cX.sub.d . . . Formula (1) where values a, b, c, and d are each greater than 0, and X is at least one selected from the group consisting of CI and Br. A battery according to the present disclosure includes a positive electrode, a negative electrode and an electrolyte layer disposed between the positive electrode and the negative electrode. At least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer includes the solid electrolyte material according to the present disclosure.