Aqueous Dual-Electrolyte Full-Cell System for Improving Energy Density of Sodium-Ion Batteries

作者：Zhou, Weishan; Zheng, Yiran; Zartashia, Mahrab; Shan, Yan^*; Noor, Hadia^*; Lou, Hongtao; Hou, Xianhua^*

来源：ACS applied materials & interfaces, 2022, 14(30): 34835-34843.

DOI：10.1021/acsami.2c06304

• aqueous sodium-ion batteries
• Prussian blue analogues
• NASICON
• redox-active electrolyte
• dual-electrolyte system

Sodium-ion batteries (SIBs) are regarded as one of the most promising candidates for next-generation energy storage devices and have been gradually grasping market share for their low cost and similar reaction mechanism and production process as compared to lithium-ion batteries. However, the low energy density of SIBs restricts their practical applications. For example, regular full cells of a Prussian blue cathode and NASICON anode have only a low discharge capacity (about 77 mA h/g at 1 C). Taking into account the compatibility of the electrolyte and electrode materials, a novel strategy for a viable aqueous dual-electrolyte sodium-ion battery (ADESIB) has been proposed using Na2SO4 solution as the anolyte and redox-active sodium hexacyanoferrate Na4Fe(CN)(6) solution as the catholyte to accommodate a NASICON NaTi2(PO4)(3) anode and Prussian blue Na2NiFe(CN)(6) cathode. The capacity of Na+ ion deinsertion/ insertion electrodes combined with the redox chemistry of the Na4Fe(CN)6 catholyte thus enhances overall charge storage and energy density. The ADESIB delivers a capacity of about 113 mA h/g at 1 C, showing a 43% improvement over batteries with a regular single Na2SO4 electrolyte. Additionally, the dual-electrolyte full-cell system is proved to reach a 84.7% capacity retention after 1000 cycles, mainly due to the synergy of the electrolytes in both sides. This pioneering research proposes an aqueous dual-electrolyte sodium-ion full cell, showing potential applications in a new sodium-ion full battery system.

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