Multiscalar Investigation of FeVO4 Conversion Cathode for a Low Concentration Zn(CF3SO3)2 Rechargeable Zn‐Ion Aqueous Battery. Issue 7 (26th March 2020)

• Record Type: Journal Article
• Authors: Kumar, Sonal; Verma, Vivek; Chua, Rodney; Ren, Hao; Kidkhunthod, Pinit; Rojviriya, Catleya; Sattayaporn, Suchinda; de Groot, Frank M. F.; Manalastas, William; Srinivasan, Madhavi
• Is Part Of: Batteries & supercaps. Volume 3:Issue 7(2020)
• Page Start: 619
• Page End: 630
• Publication Date: 2020-03-26
• Subjects: aqueous zinc-ion battery -- conversion mechanism -- tomography -- x-ray absorption spectroscopy -- electrolyte pH; Electrochemistry -- Periodicals; Electrodes -- Periodicals; Electric batteries -- Periodicals; 621.31242
• DOI: 10.1002/batt.202000018
• Languages: English
• ISSNs: 2566-6223

Abstract

Abstract: Battery cathode materials operating on multivalent‐ion intercalation are prone to short operational lifetimes, traditionally explained to be due to poor solid‐state diffusion. Here, we overcome this problem by using a conversion‐type cathode material and demonstrate the benefits in a FeVO4 host structure. The rechargeable Zn‐ion battery exhibits stability for an unprecedented operational lifetime of 57 days with a high capacity of 272 mAh g −1 (60 mA g −1 ) over 140 cycles. We use a combination of synchrotron‐based XAS, SRXTM, Raman, XRD and HRTEM techniques to elucidate the cathode material evolution at multilength‐scale for understanding the Zn‐ion storage mechanism. We further highlight the benefits of using a low‐salt concentration electrolyte and pH‐consideration analysis in aqueous battery development, the optimization of which leads to a 4‐fold increase in battery performance as compared to conventional high‐salt concentration electrolyte formulations. Abstract : Conversion‐type cathode materials may help circumvent the problem of poor solid‐state diffusion commonly occurring in intercalation‐type cathode materials for high charge‐density guest‐ions. Here, FeVO4 is demonstrated to show Zn‐ion storage by a conversion‐type mechanism, elucidated at multilength scale. The strong dependence of cycling stability on the electrolyte concentration is also demonstrated, which mechanistically relates to the electrolyte pH.