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Abstract Lithium‐ion and sodium‐ion batteries (LIBs and SIBs) are crucial in our shift toward sustainable technologies. In this work, the potential of layered boride materials (MoAlB and Mo2AlB2) as novel, high‐performance electrode materials for LIBs and SIBs, is explored. It is discovered that Mo2AlB2shows a higher specific capacity than MoAlB when used as an electrode material for LIBs, with a specific capacity of 593 mAh g−1achieved after 500 cycles at 200 mA g−1. It is also found that surface redox reactions are responsible for Li storage in Mo2AlB2, instead of intercalation or conversion. Moreover, the sodium hydroxide treatment of MoAlB leads to a porous morphology and higher specific capacities exceeding that of pristine MoAlB. When tested in SIBs, Mo2AlB2exhibits a specific capacity of 150 mAh g−1at 20 mA g−1. These findings suggest that layered borides have potential as electrode materials for both LIBs and SIBs, and highlight the importance of surface redox reactions in Li storage mechanisms.
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Fe‐Ion Bolted VOPO 4 ∙2H 2 O as an Aqueous Fe‐Ion Battery Electrode
Abstract Iron ion batteries using Fe2+as a charge carrier have yet to be widely explored, and they lack high‐performing Fe2+hosting cathode materials to couple with the iron metal anode. Here, it is demonstrated that VOPO4∙2H2O can reversibly host Fe2+with a high specific capacity of 100 mAh g−1and stable cycling performance, where 68% of the initial capacity is retained over 800 cycles. In sharp contrast, VOPO4∙2H2O's capacity of hosting Zn2+fades precipitously over tens of cycles. VOPO4∙2H2O stores Fe2+with a unique mechanism, where upon contacting the electrolyte by the VOPO4∙2H2O electrode, Fe2+ions from the electrolyte get oxidized to Fe3+ions that are inserted and trapped in the VOPO4∙2H2O structure in an electroless redox reaction. The trapped Fe3+ions, thus, bolt the layered structure of VOPO4∙2H2O, which prevents it from dissolution into the electrolyte during (de)insertion of Fe2+. The findings offer a new strategy to use a redox‐active ion charge carrier to stabilize the layered electrode materials.
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- Award ID(s):
- 2038381
- PAR ID:
- 10372144
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 33
- Issue:
- 49
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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