Work

Unveiling Oxygen Redox Activity in P2-Type NaxNi0.25Mn0.68O2 High-Energy Cathode for Na-Ion Batteries

Year: 2021

Type: article

Abstract: Na-ion batteries are emerging as convenient energy-storage devices for large-scale applications.Enhanced energy density and cycling stability are key in the optimization of functional cathode materials such as P2-type layered transition metal oxides.High operating voltage can be achieved by enabling anionic reactions, but irreversibility of O 2-/O 2 n-/O 2 evolution still limits this chance, leading to extra capacity at first cycle that is not fully recovered.Here, we dissect this intriguing oxygen redox activity in Mn-deficient Na x Ni 0.25 Mn 0.68 O 2 from first-principles, by analyzing the formation of oxygen vacancies and dioxygen complexes at different stages of sodiation.We identify low-energy intermediates that release molecular O 2 at high voltage, and we show how to improve the overall cathode stability by partial substitution of Ni with Fe.These new atomistic insights on O 2 formation mechanism set solid scientific foundations for inhibition and control of this process toward the rational design of new anionic redox-active cathode materials.

Source: ACS Energy Letters

DOI: 10.1021/acsenergylett.1c01020

Authors: Arianna Massaro, Ana B. Muñoz-García, Pier Paolo Prosini, Claudio Gerbaldi, Michele Pavone

Institutions: National Interuniversity Consortium of Materials Science and Technology, University of Naples Federico II, National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA Casaccia Research Centre, Politecnico di Torino

Language: English

Topic: Advancements in Battery Materials

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $5,000