Nitrogen-doped carbon and high-content alumina containing bi-active cobalt oxides for efficient storage of lithium

Low-content ultrathin coating of non-active alumina (Al2O3) has been extensively utilized as one of the most effective strategies to improve electrochemical performances of electrodes for lithium-ion batteries (LIBs), however, typically by employing expensive atomic layer deposition equipment. We herein demonstrate a simple preparation of high-content and well-dispersed Al2O3 (24.33wt.%)-containing multi-component composite (CoO/Co3O4/N-C/Al2O3) by calcination of melamine/CoAl-layered double hydroxide (CoAl-LDH) mixture. The resulting composite bundles the advantages expected to improve electrochemical performances: (i) bi-active CoO/Co3O4, (ii) highly conductive N-doped carbon, and (iii) N-doped carbon and high-content non-active Al2O3 as buffering reagents, as well as (iv) good distribution of bi- and non-active components resulted from the lattice orientation and confinement effect of the LDH layers. Electrochemical evaluation shows that the composite electrode delivers a highly enhanced reversible capacity of 1078mAhg(-1) after 50cycles at 100mAg(-1), compared with the bi-active CoO/Co3O4 mixtures with and without non-active Al2O3. Transmission electron microscopy/scanning electron microscopy observations and electrochemical impedance spectra experimentally provide the information on the good distributions of multiple components and the improved conductivity underlying the enhancements, respectively. Our LDH precursor-based preparation route may be extended to design and prepare various multi-component transition metal oxides for efficient lithium storage.