Enhanced ion transport by graphene oxide/cellulose nanofibers assembled membranes for high-performance osmotic energy harvesting
Enhanced ion transport by graphene oxide/cellulose nanofibers assembled membranes for high-performance osmotic energy harvesting
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DOI：
10.1039/d0mh00979b
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发表时间：
2020-10
影响因子：
13.3
通讯作者：
Yadong Wu;Weiwen Xin;Xiangyu Kong;Jianjun Chen;Yongchao Qian;Yue Sun;Xiaolu Zhao;Weipeng Chen-Weipeng-Che
中科院分区：
文献类型：
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作者：
Yadong Wu;Weiwen Xin;Xiangyu Kong;Jianjun Chen;Yongchao Qian;Yue Sun;Xiaolu Zhao;Weipeng Chen-Weipeng-Che
渗透能作为解决能源危机的新兴潜在能源越来越受到人们的关注。快速离子传输对于这种蓝色能量和其他基于膜的能量系统实现低膜电阻和功率密度的高离子选择性至关重要。然而，由于通道尺寸窄和电荷密度低，当前的纳米通道膜在离子跨膜运动方面面临着高能垒，这导致低电流和不期望的功率密度。据报道，一种精心设计的氧化石墨烯（GO）纳米片/纤维素纳米纤维（CNF）组装膜可以改善受限离子传输，从而实现高性能渗透能转换。 CNFs是最丰富的天然纳米材料，具有高度各向异性和高密度的官能团，不仅扩大了原有的狭窄通道，降低了离子传输的能垒，而且在原始GO纳米片之间引入了空间电荷以保持离子选择性。受益于GO和CNF的有效组装，通过混合人造海水和河水获得了4.19 W m−2的高功率密度和改进的电流。此外，在323 K时实现了7.20 W m−2的功率密度，高于商业化标准。由于气泡成核，渗透能转换在高温下表现出非线性热依赖关系。这种材料设计策略可以提供一种替代概念，有效增强分离、海水淡化、液流电池和燃料电池等膜基领域的离子传输。
As an emerging potential energy source to address the energy crisis, osmotic energy has attracted increasing attention. Fast ion transport is essential for this blue energy and for other membrane-based energy systems to achieve low membrane resistance and high ion selectivity for power density. However, the current nanochannel membranes suffer from a high energy barrier for ion transmembrane movement because of the narrow channel size and the low charge density, which results in low current and undesirable power density. Here, an elaborate graphene oxide (GO) nanosheets/cellulose nanofibers (CNFs) assembled membrane is reported to improve confined ion transport for high-performance osmotic energy conversion. CNFs, the most abundant natural nanomaterial with highly anisotropic properties and a high density of functional groups, not only enlarge the original narrow channel, which reduces the energy barrier for ion transport, but also introduce space charge between pristine GO nanosheets to maintain ion selectivity. Benefiting from the effective assembly of GO and CNFs, a high power density of 4.19 W m−2 with an improved current is obtained by mixing artificial seawater and river water. Moreover, a power density of 7.20 W m−2, which is higher than the standard for commercialization, is achieved at 323 K. The osmotic energy conversion shows a nonlinear thermal dependence relationship at high temperatures due to bubble nucleation. This material design strategy can provide an alternative concept to effectively enhance ion transport in membrane-based fields such as separations, desalination, flow batteries and fuel cells.