A Manganese Phosphate Cathode for Long‐Life Aqueous Energy Storage. (27th May 2021)

• Record Type: Journal Article
• Authors: Yang, Duo; Song, Yu; Zhang, Ming‐Yue; Qin, Zengming; Dong, Ran; Li, Cuicui; Liu, Xiao‐Xia
• Is Part Of: Advanced functional materials. Volume 31:Number 32(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-27
• Subjects: aqueous energy storage -- charge storage mechanism -- electrochemical deposition -- electrolyte engineering -- manganese phosphate; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202100477
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Mn‐based materials for aqueous energy storage are reaching the capacity ceiling due to the limited Mn 4+ /Mn 3+ redox. The disproportionation of Mn 3+ often occurs, forming soluble Mn 2+ and thus leading to severer capacity decays. Here, an amorphous manganese phosphate material [AMP, Na1.8 Mn4 O1.4 (PO4 )3 ] is fabricated using an electrochemical method for the first time. Benefitting from the open framework and the insoluble nature of Mn 2+ in AMP, the Mn 3+ /Mn 2+ and Mn 4+ /Mn 3+ redox couples can participate in the charge storage processes. The AMP electrode shows a high capacity of 253.4 mAh g −1 (912.4 F g −1 or 912.4 C g −1 ) at the current density 1 A g −1 and good rate capability. Experimental results indicate AMP experiences a mixed charge storage mechanism (i.e., cation intercalation and conversion reactions) in Na2 SO4 electrolyte. Besides, electrolyte engineering can effectively prevent the decomposition of AMP during cycling test, achieving capacity retention of 97% in 5000 cycles. Importantly, AMP can accommodate different cations (e.g., Mg 2+, Ca 2+, etc.), exhibiting great potential for aqueous energy storage. Abstract : An amorphous manganese phosphate material is fabricated using an electrochemical method for the first time. Benefitting from the insoluble nature of Mn 2+ in manganese phosphate, the Mn 3+ /Mn 2+ and Mn 4+ /Mn 3+ redox couples can participate in the charge storage processes, resulting in a promising electrochemical performance.