Zhang Zehao, Xu Xingtao, Ma Pin, Asakura Yusuke, Wang Zheng, Yamauchi Yusuke, Li Haibo
Ningxia Key Laboratory of Photovoltaic Materials, School of Materials and New Energy, Ningxia University, Yinchuan, China.
State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, China.
Nat Commun. 2025 Apr 17;16(1):3652. doi: 10.1038/s41467-025-58408-y.
The use of transition metal oxides to achieve capacitive deionization (CDI) via salt adsorption is based mainly on cation electrochemistry. Activating anionic (oxygen) redox chemistry can enable additional salt adsorption on transition metal oxides, but most conventional lattice oxygen‒metal configurations require high voltages (>4 V) for activation and are prone to lattice oxygen loss. Here, we propose a heterolattice oxygen-mediated redox mechanism to activate oxygen (O) redox at <2 V by constructing a VO/VCO heterostructure. Unlike the synthetic strategy based on excess Li/Na, we develop a barrier strategy based on an oxidative nucleophilic reaction using VCF as a precursor to induce the formation of heterolattice oxygen in VO/VCO heterostructures. Consequently, ultrahigh CDI performance is achieved, including a salt adsorption capacity of 185.8 mg g at 1.4 V and a salt adsorption rate of 12.1 mg g min, which exceed those of reported other faradaic materials. Further mechanistic studies reveal that the induced O electrons that dominate the Fermi level provide an additional pathway for electron movement, activating additional oxygen redox processes and forming a sodium-rich vanadate (NaVO)/VCO heterostructure. This strategy provides insights into the development of high-performance CDI materials with oxygen redox based on lattice oxygen‒metal configurations.
利用过渡金属氧化物通过盐吸附实现电容去离子化（CDI）主要基于阳离子电化学。激活阴离子（氧）氧化还原化学可以使过渡金属氧化物上额外吸附盐分，但大多数传统的晶格氧-金属构型需要高电压（>4V）来激活，并且容易出现晶格氧损失。在此，我们提出一种异质晶格氧介导的氧化还原机制，通过构建VO/VCO异质结构在<2V的电压下激活氧（O）氧化还原。与基于过量锂/钠的合成策略不同，我们开发了一种基于氧化亲核反应的势垒策略，使用VCF作为前驱体来诱导VO/VCO异质结构中异质晶格氧的形成。因此，实现了超高的CDI性能，包括在1.4V时185.8mg g的盐吸附容量和12.1mg g min的盐吸附速率，超过了报道的其他法拉第材料。进一步的机理研究表明，主导费米能级的诱导O电子为电子移动提供了额外途径，激活了额外的氧氧化还原过程，并形成了富钠钒酸盐（NaVO）/VCO异质结构。该策略为基于晶格氧-金属构型开发具有氧氧化还原的高性能CDI材料提供了思路。
