Ni-induced stepwise capacity increase in Ni-poor Li-rich cathode materials for high performance lithium ion batteries
Ni-induced stepwise capacity increase in Ni-poor Li-rich cathode materials for high performance lithium ion batteries
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DOI：
10.1007/s12274-014-0563-3
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发表时间：
2015-03
期刊：
影响因子：
9.9
通讯作者：
D. Ye;Chenghua Sun;Y. Chen;K. Ozawa;D. Hulicova‐Jurcakova;J. Zou;Lianzhou Wang
中科院分区：
文献类型：
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作者：
D. Ye;Chenghua Sun;Y. Chen;K. Ozawa;D. Hulicova‐Jurcakova;J. Zou;Lianzhou Wang
富锂正极材料被认为是很有前途的高能锂离子电池候选材料。在本研究中，我们报道了一系列新的富锂材料(Li[Li1/3−2x/3Mn2/3−x/3Nix]O2(0.09⩽x⩽0.2))作为锂离子电池的正极材料，由于Li2MnO_3相的持续激活，该材料表现出高达数十次循环的异常容量增长现象。实验和计算结果都表明，与通常研究的镍掺杂富锂正极材料不同，少量的镍掺杂可以促进Li2MnO_3的逐步活化，从而获得更高的比容量和更好的循环性能。相反，过量的镍会过度激活Li2MnO_3，导致第一次循环的容量损失很大。优化Ni含量的Li1.25Mn0.625Ni0.125O2材料具有较高的∼280mAh.g−1容量和良好的室温循环稳定性。
Li-rich cathode materials have been considered as promising candidates for high-energy lithium ion batteries (LIBs). In this study, we report a new series of Li-rich materials (Li[Li1/3−2x/3Mn2/3−x/3Nix]O2(0.09 ⩽x⩽ 0.2)) doped with small amounts of Ni as cathode materials in LIBs, which exhibited unusual phenomenon of capacity increase up to tens of cycles due to the continuous activation of the Li2MnO3phase. Both experimental and computational results indicate that unlike commonly studied Ni-doped Li-rich cathode materials, smaller amounts of Ni doping can promote the stepwise Li2MnO3activation to obtain increased specific capacity and better cycling capability. In contrast, excessive Ni will over-activate the Li2MnO3and result in a large capacity loss in the first cycle. The Li1.25Mn0.625Ni0.125O2material with an optimized content of Ni delivered a superior high capacity of ∼280 mAh·g−1and good cycling stability at room temperature.