Molten Salt Synthesis of Transition Metal Oxides doped Li 4 Ti 5 O 12 as Anode Material of Li-Ion Battery

Co 3 O 4 doped Li 4 Ti 5 O 12 compounds with protuberant nanoparticles are synthesized by molten salts method. Co 3 O 4 doping greatly decreases particle size of Li 4 Ti 5 O 12 . Combining with the result of Fe 2 O 3 doped Li 4 Ti 5 O 12 and as interstitial and substitutional atoms, transition metal atoms homogenously distribute in the crystal lattice of Li 4 Ti 5 O 12 and do not change the cubic spinel structure of Li 4 Ti 5 O 12 . As the substitutional atoms, the mixed valence of Co 3+ and Co 2+ co-exists in Li 4 Ti 5 O 12 causing O 32e or Li 8a,16d vacant sites thereby improving the electronic conductivity of Li 4 Ti 5 O 12 . The doped Li 4 Ti 5 O 12 exhibits a large first discharge capacity (173.5 mAh g -1 ) at 0.2 C rate, 144.8 mAh g -1 at 1 C rate with the capacity loss of 8.8% after 100 charge/discharge cycles and 106 mAh g -1 at 10 C. EIS analysis indicates the doped Li 4 Ti 5 O 12 electrode exhibits lower charge transfer resistance and lithium ions diffusion resistance, as optimized amounts of Co 3 O 4 produces appropriate lattice distortion and interstitial atoms in Li 4 Ti 5 O 12 .