A New CuO-Fe₂ O₃ -Mesocarbon Microbeads Conversion Anode in a High-Performance Lithium-Ion Battery with a Li_1.35 Ni_0.48 Fe_0.1 Mn_1.72 O₄ Spinel Cathode

A ternary CuO-Fe₂ O₃ -mesocarbon microbeads (MCMB) conversion anode was characterized and combined with a high-voltage Li_1.35 Ni_0.48 Fe_0.1 Mn_1.72 O₄ spinel cathode in a lithium-ion battery of relevant performance in terms of cycling stability and rate capability. The CuO-Fe₂ O₃ -MCMB composite was prepared by using high-energy milling, a low-cost pathway that leads to a crystalline structure and homogeneous submicrometrical morphology as revealed by XRD and electron microscopy. The anode reversibly exchanges lithium ions through the conversion reactions of CuO and Fe₂ O₃ and by insertion into the MCMB carbon. Electrochemical tests, including impedance spectroscopy, revealed a conductive electrode/electrolyte interface that enabled the anode to achieve a reversible capacity value higher than 500 mAh g^-1 when cycled at a current of 120 mA g^-1 . The remarkable stability of the CuO-Fe₂ O₃ -MCMB electrode and the suitable characteristics in terms of delivered capacity and voltage-profile retention allowed its use in an efficient full lithium-ion cell with a high-voltage Li_1.35 Ni_0.48 Fe_0.1 Mn_1.72 O₄ cathode. The cell had a working voltage of 3.6 V and delivered a capacity of 110 mAh g_cathode^-1 with a Coulombic efficiency above 99 % after 100 cycles at 148 mA g_cathode^-1 . This relevant performances, rarely achieved by lithium-ion systems that use the conversion reaction, are the result of an excellent cell balance in terms of negative-to-positive ratio, favored by the anode composition and electrochemical features.