Аңдатпа
The layered lithium nitridonickelate Li 2.0(1) Ni 0.67(2) N has been investigated as a negative electrode in the 0.02–1.25 V vs Li + /Li potential window. Its structural and electrochemical properties are reported. Operando XRD experiments upon three successive cycles clearly demonstrate a single-phase behavior in line with the discharge–charge profiles. The reversible breathing of the hexagonal structure, implying a supercell, is fully explained. The Ni 2+ /Ni + redox couple is involved, and the electron transfer is combined with the reversible accommodation of Li + ions in the cationic vacancies. The structural response is fully reversible and minimal, with a maximum volume variation of 2%. As a consequence, a high capacity of 200 mAh g –1 at C/10 is obtained with an excellent capacity retention, close to 100% even after 100 cycles, which makes Li 2.0(1) Ni 0.67(2) N a promising negative electrode material for Li-ion batteries.