Jina Cao Hongquan Liu Jian Xie Gaoshao Cao Xinbing Zhao
材料科学技术（英）
Ca3Co4O9 (CCO) and Ca2:95K0:05Co4O9 (CKCO) powders have been prepared by the polyacrylamide gel method. CKCO shows increased capacity and better cycling stability compared with CCO. After cycled for 50 cycles at 0.5 C, CKCO retains a capacity of 223 mAh¢g¡1, almost twice than CCO. The electrochemical impedance spectroscopy (EIS) tests shows the CKCO sample has a lower initial charge transfer resistance (Rct) and undergoes smaller Rct change during cycling than the CCO sample, indicating improved electrochemical performance by K-doping.
关键词:
Lithium-ion battery
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Anode
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Ca3Co4O9
,
K-doping
G.X.Wang
,
Steve Bewlay
,
L.Yang
,
J.Z.Wang
,
Y.Chen
,
Jane Yao
,
H.K.Liu
,
S.X.Dou
材料科学技术（英）
Nanocrystalline LiFePO4 and Si-C powders were prepared as electrode materials for lithium-ion batteries. Near full capacity (170 mAh/g) was achieved at the C/8 rate at room temperature for LiFePO4 electrodes. Nanosize Si-C composite anode materials demonstrated a reversible lithium storage capacity of 1450 mAh/g with good cyclability when used as anodes in lithium-ion cells. Nanostructured electrode materials have an important role to play in developing a new generation of lithium-ion batteries that will offer a dramatic improvement in power delivery.
关键词:
Lithium-ion battery
,
null
,
null
,
null
Y.X. Chen L.H. He P.J. Shang Q.L. Tang Z.Q. Liu H.B. Liu L.P. Zhou
材料科学技术（英）
Micro-sized (1030.3§178.4 nm) and nano-sized (50.4±8.0 nm) Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal process. The morphology and microstructure of the micro-sized and the nano-sized Fe3O4 particles were characterized by X-ray diffraction, field-emission gun scanning electron microscopy, transmission electron microscopy and high-resolution electron microscopy. The micro-sized Fe3O4 particles exhibit porous structure, while the nano-sized Fe3O4 particles are solid structure. Their electrochemical performance was also evaluated. The nano-sized solid Fe3O4 particles exhibit gradual capacity fading with initial discharge capacity of 1083.1 mAhg¡1 and reversible capacity retention of 32.6% over 50 cycles. Interestingly, the micro-sized porous Fe3O4 particles display very stable capacity-cycling behavior, with initial discharge capacity of 887.5 mAhg¡1 and charge capacity of 684.4 mAhg−1 at the 50th cycle. Therefore, 77.1% of the reversible capacity can be maintained over 50 cycles. The micro-sized porous Fe3O4 particles with facile synthesis, good cycling performance and high capacity retention are promising candidate as anode materials for high energy-density lithium-ion batteries.
关键词:
Lithium-ion battery
,
null
,
null
Y.X. Chen L.H. He P.J. Shang Q.L. Tang Z.Q. Liu H.B. Liu L.P. Zhou
材料科学技术（英）
Micro-sized (1030.3§178.4 nm) and nano-sized (50.4±8.0 nm) Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal process. The morphology and microstructure of the micro-sized and the nano-sized Fe3O4 particles were characterized by X-ray diffraction, field-emission gun scanning electron microscopy, transmission electron microscopy and high-resolution electron microscopy. The micro-sized Fe3O4 particles exhibit porous structure, while the nano-sized Fe3O4 particles are solid structure. Their electrochemical performance was also evaluated. The nano-sized solid Fe3O4 particles exhibit gradual capacity fading with initial discharge capacity of 1083.1 mAhg¡1 and reversible capacity retention of 32.6% over 50 cycles. Interestingly, the micro-sized porous Fe3O4 particles display very stable capacity-cycling behavior, with initial discharge capacity of 887.5 mAhg¡1 and charge capacity of 684.4 mAhg−1 at the 50th cycle. Therefore, 77.1% of the reversible capacity can be maintained over 50 cycles. The micro-sized porous Fe3O4 particles with facile synthesis, good cycling performance and high capacity retention are promising candidate as anode materials for high energy-density lithium-ion batteries.
关键词:
Lithium-ion battery
,
null
,
null
邓洪贵
,
金双玲
,
詹亮
,
金鸣林
,
凌立成
新型炭材料
doi:10.1016/S1872-5805(14)60139-6
采用溶剂热反应并经在氮气中煅烧的方法制备出不同形貌的 Fe 3 O 4/ C 纳米复合物。无需表面活性剂或模板剂,仅通过调控反应物的浓度,合成出花状、纳米片状、空心球形结构3种纳米结构,并对不同形貌的形成机理进行探讨。此外,三种不同形貌样品的电化学结果表明,花状样品的电化学综合性能显著优于另外两种形貌,在5 C 的充放电电流下,其可逆比容量能达到227 mAh/ g,而空心球形、纳米片状结构样品的容量则分别为45、10 mAh/ g。
关键词:
Fe3O4
,
纳米复合材料
,
负极材料
,
锂离子电池
