Interior-Confined Vacancy in Potassium Manganese Hexacyanoferrate for Ultra-Stable Potassium-Ion Batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38230871.
- Also identified by DOI 10.1002/adma.202310428.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Metal hexacyanoferrates (HCFs) are viewed as promising cathode materials for potassium-ion batteries (PIBs) because of their high theoretical capacities and redox potentials. However, the development of an HCF cathode with high cycling stability and voltage retention is still impeded by the unavoidable Fe(CN)<sub>6</sub> vacancies (V<sub>FeCN</sub>) and H<sub>2</sub>O in the materials. Here, a repair method is proposed that significantly reduces the V<sub>FeCN</sub> content in potassium manganese hexacyanoferrate (KMHCF) enabled by the reducibility of sodium citrate and removal of ligand H<sub>2</sub>O at high temperature (KMHCF-H). The KMHCF-H obtained at 90 °C contains only 2% V<sub>FeCN</sub>, and the V<sub>FeCN</sub> is concentrated in the lattice interior. Such an integrated Fe-CN-Mn surface structure of the KMHCF-H cathode with repaired surface V<sub>FeCN</sub> allows preferential decomposition of potassium bis(fluorosulfonyl)imide (KFSI) in the electrolyte, which constitutes a dense anion-dominated cathode electrolyte interphase (CEI) , inhibiting effectively Mn dissolution into the electrolyte. Consequently, the KMHCF-H cathode exhibits excellent cycling performance for both half-cell (95.2 % at 0.2 Ag<sup>-1</sup> after 2000 cycles) and full-cell (99.4 % at 0.1 Ag<sup>-1</sup> after 200 cycles). This thermal repair method enables scalable preparation of KMHCF with a low content of vacancies, holding substantial promise for practical applications of PIBs.