A high energy density full lithium-ion cell based on specially matched coulombic efficiency

Abstract

Nano-spherical Li-rich cathodes and Mn_xCo_1−xO anodes are synthesized from as-solvothermal Mn_xCo_1−xCO₃ (x = 1, 0.8, and 0.5) precursors. Based on the half-cell studies of these materials, Li-rich 0.5Li₂MnO₃·0.5LiMn_0.5Ni_0.5O₂ with a high reversible capacity of 247 mA h g⁻¹ and binary transition metal oxide Mn_0.8Co_0.2O with a reversible capacity of 759 mA h g⁻¹ are selected respectively as the optimal positive and negative electrodes to construct a full cell. Such an electrode match-up, i.e. Li-rich/Mn_0.8Co_0.2O full cell (“N-cell”), allows no need for pre-activation of the metal oxide anode. This “N-cell” can deliver a high reversible capacity of 205 mA h g⁻¹ and particularly rather high volumetric energy density, which is about 31% higher than that of a Li-rich/graphite full cell (“T-cell”). The special coulombic efficiency match-up and tailored microstructures and compositions of the electrode materials are all crucial to achieve such a high energy density.