Sn–C and Se–C Co-Bonding SnSe/Few-Layered Graphene Micro–Nano Structure: Route to a Densely Compacted and Durable Anode for Lithium/Sodium-Ion Batteries

Abstract

Developing anodes with a high and stable energy density for both gravimetric and volumetric storage is vital for high-performance lithium/sodium-ion batteries. Herein, an SnSe/few-layered graphene (FLG) composite with a high tap density (2.3 g cm −3 ) is synthesized via the plasma-milling method, in which SnSe nanoparticles are strongly bound with the FLG matrix, owing to both Sn−C and Se−C bonds, to form nanosized primary particles and then assemble to microsized secondary granules. The FLG can effectively alleviate the large stress generated from the volume expansion of SnSe during cycling based on its superstrength. Furthermore, as demonstrated by the density-functional theory calculations, the Sn−C and Se−C co-bonding benefitting from the formation of substantial vacancy defects on the P-milling-synthesized FLG enables strong affinity between SnSe nanoparticles and the FLG matrix, preventing SnSe from aggregating and detaching even after long-term cycling. As an anode for lithium-ion batteries, it exhibits high gravimetric and volumetric capacities (864.8 mAh g −1 and 1990 mAh cm −3 at 0.2 A g −1 ), a high rate (612.6 mAh g −1 even at 5.0 A g −1 ), and the longest life among the reported SnSe-based anodes (capacity retention of 92.8% after 2000 cycles at 1.0 A g −1 ). Subsequently, an impressive cyclic life (capacity retention of 91.6% after 1000 cycles at 1.0 A g −1 ) is also achieved for sodium-ion batteries. Therefore, the SnSe/FLG composite is a promising anode for high-performance lithium/sodium-ion batteries.

Single Semi‐Metallic Selenium Atoms on Ti3C2 MXene Nanosheets as Excellent Cathode for Lithium–Oxygen Batteries

“…TiO peaks show a distinct upshifting tendency, and TiC peaks possess a down-shifting phenomenon after the loading of Se SAs, which is mainly caused by the formation of SeC bonds and increasing content of the surface oxygen-containing functional groups. [30,32] Meanwhile, the replacement of CF located at 287.6 eV by a new peak at 288.8 eV belonging to CSe suggests the anchoring of Se SAs. [33,34] Moreover, Se K-edge X-ray absorption near-edge structure (XANES) spectrum of SASe-Ti 3 C 2 as well as Se foil and SeO 2 is used to further reveal the electron structure of Se SAs.…”

“…A weak peak at 58.7 eV can be assigned to SeC/SeO bond, demonstrating that Se SAs were immobilized in two ways described as filling in V Ti and bonding with surface oxygen‐containing terminal groups. [ 30,31 ] Furthermore, CSe peak in Raman spectrum (Figure S7, Supporting Information) is observed at 208 cm −1 in SASe–Ti 3 C 2 catalyst, indicating the combination between Se SAs and Ti 3 C 2 substrate. [ 30 ] The enhancement of the G‐ and D‐bands suggests the increase in carbon content, and the increased I D / I G ratio evidences a highly disordered (amorphous) structure of Ti 3 C 2 substrate after the CO 2 thermal treatment.…”

“…[ 30,31 ] Furthermore, CSe peak in Raman spectrum (Figure S7, Supporting Information) is observed at 208 cm −1 in SASe–Ti 3 C 2 catalyst, indicating the combination between Se SAs and Ti 3 C 2 substrate. [ 30 ] The enhancement of the G‐ and D‐bands suggests the increase in carbon content, and the increased I D / I G ratio evidences a highly disordered (amorphous) structure of Ti 3 C 2 substrate after the CO 2 thermal treatment. High‐resolution XPS spectra of Ti 2p and C 1s (Figure 2b,c) can further reveal the change in chemical states.…”

A General Strategy for Antimony‐Based Alloy Nanocomposite Embedded in Swiss‐Cheese‐Like Nitrogen‐Doped Porous Carbon for Energy Storage

“…[ 11 ] Therefore, in this study, by introducing a strong MN covalent bond to construct an SbMNC structure, it may help to enhance the interfacial ion storage capacity and stability between the alloy and the carbon material, while preventing the alloy from falling off and avoiding agglomeration. [ 12 ] In addition, heteroatom doping can further stimulate the carbon matrix to generate more active sites for energy storage as well as improving electrical conductivity. [ 13 ]…”

“…[11] Therefore, in this study, by introducing a strong MN covalent bond to construct an SbMNC structure, it may help to enhance the interfacial ion storage capacity and stability between the alloy and the carbon material, while preventing the alloy from falling off and avoiding agglomeration. [12] In addition, heteroatom doping can further stimulate the carbon matrix to generate more active sites for energy storage as well as improving electrical conductivity. [13] Herein, we propose a general and scalable strategy for the fabrication of MSb (M = Ni, Co, or Fe) alloy nanocomposites anchored on Swiss-cheese-like nitrogen-doped porous carbon with MNC coordination (with the product denoted as MS@ NPC) through the spontaneous template method.…”