SECONDARY BATTERY, BATTERY PACK, AND VEHICLE

Abstract

In general, according to an embodiment, a secondary battery includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode contains a niobium-containing oxide. In hard X-ray photoelectron spectroscopy on a surface of the negative electrode, a ratio B/A of an area B in a range of 680 eV or more and 695 eV or less to an area A in a range of 200 eV or more and 215 eV or less is 1.1 or more and 4.3 or less. The electrolyte contains a lithium salt and a first carboxylate ester. A content of the first carboxylate ester is 70 mass % or more and 95 mass % or less with respect to 100 mass % of the electrolyte excluding the lithium salt.

CPC Classifications