SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells – Insights from ²³Na In‐Situ Solid‐State NMR

Abstract

Polymer-derived silicon carbonitride ceramic (SiCN) is used as an electrode material to prepare cylindrical sodium/sodium ion cells for solid-state NMR investigations. During galvanostatic cycling structural changes of the environment of sodium/ sodium ions are investigated by applying 23 Na in-situ solid-state NMR. Changes of the signals assigned to sodium metal, intercalated sodium cation and sodium cation originating from the electrolyte are monitored as well as the occurrence of an additional signal in the region of metallic sodium. The intensity of this additional signal changes periodically with the cycling process indicating the reversibility of structures formed and deformed during the galvanostatic cycling. To identify interactions of sodium/sodium ions with the SiCN electrode materials, the cycled SiCN material is studied by 23 Na ex-situ MAS NMR at high spinning rates of 20 and 50 kHz to obtain appropriate spectral resolution.

On the Reversible Sodium Plating/stripping Reaction in Porous SiCN(O) Ceramic: A Feasibility Study

“…During the first voltamperometric reduction cycle in a SiCN(O)-P/NaPF 6 /Na cell, a cathodic peak is registered at a potential of approximately 0.014 V and correlated to the anodic peak appearing at around 0.12 V. This redox couple is attributed to a reversible insertion/extraction of sodium ions. While extending the potential range to À 0.03 V, an additional cathodic peak is detected at around À 0.03 V revealing the formation of a metallic Na species whose presence has been recently confirmed employing "in-situ" NMR measurement by Šić et al [33] The corresponding anodic peak is superimposed with the anodic sodium ion extraction leading to a slightly shifted peak at 0.11 V. To determine the amount of capacity originating from sodium insertion into the porous SiCN(O), a galvanostatic measurement in a range between 0.005 V and 2.5 V has been performed (Figure 2c). An insertion/extraction capacity equal to 340 mAh g À 1 and 113 mAh g À 1 respectively has been measured in the first cycle.…”

Wide-temperature-range sodium-metal batteries: from fundamentals and obstacles to optimization

“…508,509 The abundant NMR-active nuclei cover most of the constituent elements of battery materials, which makes in situ static NMR spectroscopy highly compatible with battery technology. 457,510 Specifically, as charge carriers, 6/7Li and 23Na are directly involved in the electrochemical processes of LIBs and SIBs, respectively, and have emerged as the most frequently probed atoms in the field of energy-storage technology. 511,512…”

SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid‐State NMR and DFT Calculations

“…In this context, a variety of novel materials with tailored properties have been explored for use as electrodes in batteries, replacing the commercially utilized graphite [2,3] . Silicon‐based polymer‐derived ceramics (PDCs) including silicon oxycarbide (SiCO) or silicon carbonitride (SiCN) have been proven as efficient electrode materials for rechargeable lithium batteries, [2,4,5] and very recently for Na/Na + cell model systems as the basis for sodium batteries [6,7] . The amorphous covalent framework of SiCO/SiCN, where Si atoms are coordinated to O as well as to C or N and where domains of disordered free carbon nanosheets are assumed, enables reversible lithium storage with improved charge capacity compared to conventional graphite electrodes.…”

“…[2,3] Silicon-based polymer-derived ceramics (PDCs) including silicon oxycarbide (SiCO) or silicon carbonitride (SiCN) have been proven as efficient electrode materials for rechargeable lithium batteries, [2,4,5] and very recently for Na/Na + cell model systems as the basis for sodium batteries. [6,7] The amorphous covalent framework of SiCO/SiCN, where Si atoms are coordinated to O as well as to C or N and where domains of disordered free carbon nanosheets are assumed, enables reversible lithium storage with improved charge capacity compared to conventional graphite electrodes. Hereby, the PDCs do not undergo large volume expansion and thus supply better cycling performance than the analogous graphite materials, [8,9] making them excellent candidates as electrodes for all-solid-state batteries.…”