Genuine Unilamellar Metal Oxide Nanosheets Confined in a Superlattice-like Structure for Superior Energy Storage
Genuine Unilamellar Metal Oxide Nanosheets Confined in a Superlattice-like Structure for Superior Energy Storage
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真正的单层金属氧化物纳米片被限制在超晶格结构中，以实现卓越的能量存储
DOI：
10.1021/acsnano.7b08522
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发表时间：
2018
期刊：
影响因子：
17.1
通讯作者：
Sasaki Takayoshi
中科院分区：
文献类型：
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作者：
Xiong Pan;Ma Renzhi;Sakai Nobuyuki;Sasaki Takayoshi
二维金属氧化物纳米片具有较短的离子扩散距离、丰富的活性位点和多种价态，具有优异的电化学性能。特别是，具有原子尺度厚度的真正单层纳米片有望表现出最终的能量存储能力，但尚未实现其潜力。在这里，我们展示了利用真正的单层MnO2纳米片，使用交替堆叠的MnO2/石墨烯超晶格结构，用于高性能的Li和Na存储。与之前的报道不同，所有单层二氧化锰纳米片都在石墨烯单层之间分离和稳定，导致高度可逆的2d限制转化过程。结果表明，在0.1 a g-1条件下，锂和钠的比容量分别为1325和795 mA h g-1，在12.8 a g-1条件下，高倍率容量分别为370和245 mA h g-1，在5000次循环后，锂和钠的循环稳定性分别为0.004%和0.0078%，呈现出迄今为止报道的最佳性能。
Two-dimensional (2D) metal oxide nanosheets can exhibit exceptional electrochemical performance owing to their shortened ion diffusion distances, abundant active sites, and various valence states. Especially, genuine unilamellar nanosheets with an atomic-scale thickness are expected to exhibit the ultimate energy storage capability but have not yet achieved their potential. Here, we demonstrate the utilization of genuine unilamellar MnO2nanosheets for high-performance Li and Na storage using an alternately stacked MnO2/graphene superlattice-like structure. Different from previous reports, all unilamellar MnO2nanosheets are separated and stabilized between the graphene monolayers, resulting in highly reversible 2D-confined conversion processes. As a consequence, large specific capacities of 1325 and 795 mA h g–1at 0.1 A g–1, high-rate capacities of 370 and 245 mA h g–1at 12.8 A g–1, and excellent cycling stabilities after 5000 cycles with ∼0.004% and 0.0078% capacity decay per cycle were obtained for Li and Na storage, respectively, presenting the best reported performance to date.