Secondary battery, battery pack, vehicle, and stationary power supply

Abstract

According to one embodiment, provided is a secondary battery including an aqueous electrolyte, a positive electrode, and a negative electrode, where the negative electrode includes a negative electrode active material containing a Ti-containing composite oxide. At least one element A selected from the group consisting of Hg, Pb, Zn, and Bi is present on a surface of the negative electrode. An average of molar ratios (A/(A+Ti)) of the element A is more than or equal to 5% and less than or equal to 40%. Each of the molar ratios is a molar amount of the element A to a sum between the molar amount of the element A and a molar amount of Ti on the surface of the negative electrode, according to scanning electron microscopy-energy dispersive X-ray spectroscopy.

Dependencies are inferred from the claim text.