Cu/Co binary-transition metal glycerolates as anode materials for lithium-ion batteries

The energy density of Lithium-ion batteries (LiBs) fails to keep pace with the growing demand for long-driving range EVs. Developing novel anode materials with high specific capacities is one of the most effective ways to increase the energy density of LiBs. Herein, a series of Cu and Co binary-transition metal glycerolates (labeled as Cu_xCo_y/G) were prepared as the anodes for LiBs. It was observed that Cu_xCo_y/G exhibited a distinctive yolk-shell architecture, which significantly differed from the solid spherical structure of Cu/G and Co/G counterparts. X-ray powder diffraction and Scanning electron microscope studies suggested that Cu element existed as Cu₂₊₁O in Cu_xCo_y/G, and the Co element was in the form of amorphous glycerolates. Electrochemical studies showed that Cu_0.4Co₁/G delivered a high capacity over 1000 mAh g⁻¹ at the first discharge, and it exhibited the most stable cycling performance over 200 cycles. Mechanism study suggested both Cu and Co elements contributed to lithium storage capacities in Cu_xCo_y/G at the initial discharging process. Experimental results revealed that Co exhibited reversible capacity while Cu element was reduced to metallic Cu which contributed to the electronic conductivity, rendering Cu_0.4Co₁/G exhibited a better long-term cycling stability than Co/G. This work explored a new type of anode material with high specific capacity for LiBs, paving the way to high energy density LiBs.