Understanding Na2Ti3O7 as an ultra-low voltage anode material for a Na-ion battery

An in-depth understanding of Na2Ti3O7 as a Na-ion battery anode is reported. The battery performance is enhanced by carbon coating, due to increased electronic conductivity and reduced solid electrolyte interphase formation. Ti4+ reduction upon discharge is demonstrated using in situ XAS. The self-relaxation behaviour of the fully intercalated phase is revealed.