Abstract: In general, according to one embodiment, a secondary battery includes a positive electrode and a nonaqueous electrolyte. The positive electrode includes a sulfur-containing layer provided on at least a part of a positive electrode active material-containing layer. The nonaqueous electrolyte includes a sulfur-containing compound consisting of at least one of a sulfur-containing imide compound or a sultone compound, or consisting of at least one of a sulfur-containing imide compound, a sultone compound or a propanesulfonic acid ester. The secondary battery satisfies 1×10?6?E/A?9×10?4. A denotes a mass of sulfur atoms per unit volume (g/m3) of the sulfur-containing layer. E denotes a concentration (mol/L) of the sulfur-containing compound in the nonaqueous electrolyte.

Abstract: According to one embodiment, a method of producing a secondary battery includes preparing a battery architecture, which includes a positive electrode, a negative electrode, and an electrolyte, providing a potential adjusted state by adjusting a positive electrode potential to 4.3 V to 4.8 V and a negative electrode potential to 0.5 V to 1.1 V based on oxidation-reduction potential of lithium, and holding the battery architecture in the potential adjusted state. The positive electrode includes a nickel-containing oxide represented by a general formula LixM1O2. M1 is a metal element including at least Ni in an elemental ratio of 50% or more, and 0<x?1. The negative electrode includes a titanium-containing oxide. The electrolyte includes a sulfur-containing compound.