CAJ | 학술논문

以氢氧化铝溶胶为前驱体在LiNi0.5 Mn1.5 O4正极材料表面制备尖晶石结构γ-Al2 O3包覆层，借助XRD、SEM、TEM及电化学方法对电极材料的主要性能进行了研究。结果表明：LiNi0.5 Mn1.5 O4表面γ-Al2 O3包覆层形成条件为600℃下煅烧0.5 h，较佳包覆量约为3％（摩尔比）；γ-Al2 O3包覆层形貌完整，厚度约为5～10 nm，（311）晶面间距约0.24 nm；γ-Al2O3包覆的LiNi0.5Mn1.5O4正极材料30周充放电循环（0.2 C）后的比容量为112.1 mAh／g，4 C倍率下的比容量为82.0 mAh／g，容量保持率较基体分别提高了约10％和17.2％。因此，γ-Al2 O3包覆层减小了LiNi0.5 Mn1.5 O4与电解液的接触，有效抑制了基体与电解液之间的副反应，其电化学反应可逆性、循环稳定性及倍率性能得到了提高，有望用作动力锂离子电池正极材料。
이경양화려용효위전구체재LiNi0.5 Mn1.5 O4정겁재료표면제비첨정석결구γ-Al2 O3포복층，차조XRD、SEM、TEM급전화학방법대전겁재료적주요성능진행료연구。결과표명：LiNi0.5 Mn1.5 O4표면γ-Al2 O3포복층형성조건위600℃하단소0.5 h，교가포복량약위3％（마이비）；γ-Al2 O3포복층형모완정，후도약위5～10 nm，（311）정면간거약0.24 nm；γ-Al2O3포복적LiNi0.5Mn1.5O4정겁재료30주충방전순배（0.2 C）후적비용량위112.1 mAh／g，4 C배솔하적비용량위82.0 mAh／g，용량보지솔교기체분별제고료약10％화17.2％。인차，γ-Al2 O3포복층감소료LiNi0.5 Mn1.5 O4여전해액적접촉，유효억제료기체여전해액지간적부반응，기전화학반응가역성、순배은정성급배솔성능득도료제고，유망용작동력리리자전지정겁재료。
γ-Al2 O3-coated LiNi0.5 Mn1.5 O4 cathode material was prepared using aluminum hydroxide sol as pre-cursors.The properties of samples were characterized by XRD,SEM,TEM and electrochemical methods.The results indicate that the complete and compactγ-Al2 O3 nanoshell can be obtained by sintering at 600 ℃for 0.5 h with Al2 O3/LiNi0.5 Mn1.5 O4 mole ratio of 3%.The coating thickness is about 5 -10 nm.The crystal face is clear and the interplanar spacing of (3 1 1 )is about 0.24 nm.Al2 O3-coated samples can still deliver a discharge capacity of 1 12.1 mAh/g and 82.0 mAh/g respectively after 30 full charge-discharge cycles at constant rates of 0.2 C and 4 C.Al2 O3-coated LiNi0.5 Mn1.5 O4 samples show outstanding cyclability.The capacities of Al2 O3-coated samples are 10% and 17.2% higher than that of the bare ones after 30 charge-discharge cycles at rates of 0.2 C and 4 C respectively.These mean that the Al2 O3 coating can effectively separate the electrolyte and LiNi0.5Mn1.5O4,which depresses the side reactions,resulting in better cycling performance,better rate capabil-ity,and better rate capability retention during cycling.These results prove thatγ-Al2 O3-coated LiNi0.5 Mn1.5 O4 is a very promising cathode material.