Synthesis, Electrochemical Properties, and Thermal Stability of Al-Doped LiNisub 1∕3Mnsub 1∕3Cosub (1∕3−z)Alsub zOsub 2 Positive Electrode Materials

Al-doped Li Ni 1 ∕ 3 Mn 1 ∕ 3 Co ( 1 ∕ 3 − z ) Al z O 2 ( 0 ⩽ z ⩽ 0.14 ) samples were synthesized using a coprecipitation method followed by calcination with Li O H ⋅ H 2 O at 500 ° C for 3 h and 900 ° C for 3 h . Electrochemical testing showed that Li Ni 1 ∕ 3 Mn 1 ∕ 3 Co ( 1 ∕ 3 − z ) Al z O 2 had a high initial discharge capacity and good charge–discharge cycle performance in the voltage ranges of either 2.5–4.3 or 2.5 – 4.6 V . The impact of Al doping on the thermal stability of Li Ni 1 ∕ 3 Mn 1 ∕ 3 Co ( 1 ∕ 3 − z ) Al z O 2 was studied by accelerating rate calorimetry. Al substitution for Co in Li Ni 1 ∕ 3 Mn 1 ∕ 3 Co 1 ∕ 3 O 2 caused a dramatic improvement in thermal stability over the material without aluminum. Al-doped Li { Ni 1 ∕ 3 Mn 1 ∕ 3 Co ( 1 ∕ 3 − z ) Al z ] O 2 with z = 0.1 displays an energy density greater than Li Mn 2 O 4 and equivalent or higher thermal stability, making it a possible choice as an electrode material for large Li-ion batteries.