All-solid-state battery and manufacturing method thereof

Abstract

Use of silicon as a negative electrode active material particle causes a problem of expansion and contraction of the negative electrode active material particle due to charging and discharging. A negative electrode active material particle or a plurality of negative electrode active material particles are bound or fixed using a graphene compound to inhibit expansion and contraction of the negative electrode active material particle due to charging and discharging. In an all-solid-state secondary battery, an interface between a solid electrolyte and a negative electrode or an interface between the solid electrolyte and a positive electrode has the highest resistance. In order to reduce the interface resistance, at least the negative electrode active material particle is surrounded by a graphene compound to increase the conductivity. Alternatively, a positive electrode active material particle is surrounded by a graphene compound to increase the conductivity. Carrier ions, e.g., lithium ions, pass through a graphene compound, and thus the graphene compound does not hinder the transfer of lithium ions between the positive electrode and the negative electrode in charging or discharging.