Mixed alkali-ion transport and storage in atomic-disordered honeycomb layered NaKNi2TeO6

Titus Masese,Cédric Tassel,Tamio Ikeshoji,Yoshinobu Miyazaki,Godwill Mbiti Kanyolo,Masatomo Yashima,Kotaro Fujii,Hiroshi Kageyama,Toshiyuki Matsunaga,Yoshiharu Uchimoto,Hiroshi Senoh,Jinkwang Hwang,Miyu Ito,Hiroki Ubukata,Chih-Yao Chen,Kartik Sau,Zhen-Dong Huang,Keigo Kubota,Abbas Alshehabi,Josef Rizell,Rika Hagiwara,Kazuhiko Matsumoto,Kazuki Yoshii,Terüo Takahashi ,Masahiro Shikano,Tomohiro Saito

doi:10.1038/s41467-021-24694-5

Abstract

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms (Na and K) to produce a mixed-alkali honeycomb layered oxide material, namely, NaKNi2TeO6. Via transmission electron microscopy measurements, we reveal the local atomic structural disorders characterised by aperiodic stacking and incoherency in the alternating arrangement of Na and K atoms. We also investigate the possibility of mixed electrochemical transport and storage of Na+ and K+ ions in NaKNi2TeO6. In particular, we report an average discharge cell voltage of about 4 V and a specific capacity of around 80 mAh g–1 at low specific currents (i.e., < 10 mA g–1) when a NaKNi2TeO6-based positive electrode is combined with a room-temperature NaK liquid alloy negative electrode using an ionic liquid-based electrolyte solution. These results represent a step towards the use of tailored cathode active materials for “dendrite-free” electrochemical energy storage systems exploiting room-temperature liquid alkali metal alloy materials.

Highlights

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties
Honeycomb layered oxides are a family of lamellarstructured nanomaterials characterised mainly by alkali or coinage-metal atoms interleaved between sheets of transition metal atoms aligned in a honeycomb formation
The intermixing of alkali ions appears to be a judicious approach to the level development of honeycomb layered oxides, as far as we can tell, only one report on a set of metastable antimonates Li3-xNaxNi2SbO6 has been published on the topic24

Summary

Introduction

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. We report an average discharge cell voltage of about 4 V and a specific capacity of around 80 mAh g–1 at low specific currents (i.e., < 10 mA g–1) when a NaKNi2TeO6-based positive electrode is combined with a roomtemperature NaK liquid alloy negative electrode using an ionic liquid-based electrolyte solution These results represent a step towards the use of tailored cathode active materials for “dendrite-free” electrochemical energy storage systems exploiting room-temperature liquid alkali metal alloy materials. Honeycomb layered oxides are a family of lamellarstructured nanomaterials characterised mainly by alkali or coinage-metal atoms interleaved between sheets of transition metal atoms aligned in a honeycomb formation This emerging class has been gaining momentous interest as a result of a variety of appealing properties innate to their structural framework. The intermixing of alkali ions appears to be a judicious approach to the level development of honeycomb layered oxides, as far as we can tell, only one report on a set of metastable antimonates Li3-xNaxNi2SbO6 has been published on the topic

Methods

Results

Conclusion