A stable graphite negative electrode for the lithium–sulfur battery

Abstract

Efficient, reversible lithium intercalation into graphite in ether-based electrolytes is enabled through a protective electrode binder, polyacrylic acid sodium salt (PAA-Na). In turn, this enables the creation of a stable “lithium-ion–sulfur” cell, using a lithiated graphite negative electrode with a sulfur positive electrode, using the common DME:DOL solvent system suited to the electrochemistry of the lithium–sulfur battery. Graphite–sulfur lithium-ion cells show average coulombic efficiencies of ∼99.5%, compared with <95% for lithium–sulfur cells, and significantly better capacity retention, taking into account cell balancing considerations. The high efficiency derives from the considerably better interfacial stability of the graphite electrode, which suppresses the polysulfide redox shuttle and self-discharge.