A core@double‐shell structured silicon/ flower‐like manganese selenide/carbon composite as superior dual anode materials of Li/Na‐ion batteries

Abstract

Summary One of the feasible solutions for enhancing new energy density of secondary batteries is to develop high‐performance dual anode materials for lithium and sodium‐ion batteries (LIBs&SIBs). To address this key challenge, we introduce a novel silicon/flower‐like manganese selenide/carbon composite (Si@MnSe@PPyC/rGO) with core@double‐shell structure as potential dual anode materials. The morphology, structure and composition of the composite are determined by means of SEM, TEM, EDS, XRD, Raman, TGA and XPS. The key to the successful synthesis process is that in situ polymerization of polypyrrole on the nanosheet of flower‐like Si@MnO2 preserves the intermediate layer with flower‐like morphology during selenization. Si@MnSe@PPyC/rGO exhibits the high performance owing to exceptional advantages such as the high capacity silicon core, the stable flower‐shaped MnSe and PPyC double shells as protective layer, as well as the excellent conductive network of rGO. This material delivers a greatly enhanced reversible capacity (803 mAh/g at 0.1 A/g), remarkable stability and excellent rate performance (437 mAh/g even at 3.2 A/g) in LIBs. For Na‐ion storage, it pleasantly reaches 323 mAh/g at 0.2 A/g and remains constant at 226.4 mAh/g after 500 cycles at 2.0 A/g. This study provides versatile strategy so as to maintain the unique morphology of nano‐metal oxide during selenization treatment, and supplies a cost‐effective strategy for preparing high‐performance dual‐anode materials for Li/Na‐ion storage. Novelty Statement Novel silicon/flower‐like manganese selenide/carbon composites (Si@MnSe@PPyC/rGO) with core@double‐shell structure are successfully fabricated as superior dual anode materials for Li/Na‐ion storage for the first time. The critical step is the in‐situ coating of PPy on the surface of nanosheets of Si@flower‐like MnO2 which could remain the original flower‐like morphology unchanged during selenization treatment. Si@MnSe@PPyC/rGO exhibits excellent potential as a dual anode material candidate for high performance Li/Na‐ion storage including high capacity, stable cycling performance and high rate capability.

Boosting Manganese Selenide Anode for Superior Sodium-Ion Storage via Triggering α → β Phase Transition

“…Ultralong cycling lifetime over 1000 cycles is acquired for δ−α-MnSe at 1000 mA·g –1 in Figure f, whose reversible capacity cycles from 111.1 to 81.4 mAh·g –1 , exhibiting lower capacity fading rate of 0.0267% per cycle. As exhibited in Figure g and Table S3, δ−α-MnSe displays great cycling stability among the reported α-MnSe anodes and other ever-published intercalation-type, organic, conversion, alloying, and conversion-alloying anode materials for SIBs. ,,− Figure S11 and Table S4 also compare the rate performances of previously reported anodes with this work, where δ−α-MnSe exhibits great rate capability at various current densities. ,− ,,,,, …”

Binder-Free Intertwined Si and MnO2 Composite Electrode for High-Performance Li-Ion Battery Anode

“…During the first discharge, the cathodic peak appears near 0.25 V is attributed to the irreversible lithiation of the Si–O surface layer, , and the peaks disappear in the following cycles. The cathodic peak around 0.01 and 0.17 V corresponds to Li + embedding into Si to form the Li–Si alloy, while the two anodic peaks at 0.30 and 0.48 V are due to the Li + extraction forming Li x Si alloy. − In the subsequent cycles, the broad and weak cathodic peak at around 0.60 V could be ascribed to the formation of a solid electrolyte interface (SEI) of the electrolyte decomposition. Furthermore, compared with the Si film (Figure S4a), both Si-MO and MnO 2 films have better reversibility, but the MnO 2 film is more inclined to capacitance characteristics (Figure S4b).…”

Si@Nitrogen-Doped Carbon Nanoparticles for Lithium-Ion Battery Anodes

“…(c) Schematic illustration of the preparation processes of Si@NC. (d) Comparison of the electrochemical performance for Si@NC in this work and previously reported Si-based anodes with a single-layer or multilayer carbon coating for LIBs. ,,− …”

“…Various strategies have been put forward to address the problems of a Si-based anode; ,, among them, reducing the size of Si particles serves to diminish the relative volume change, , and encasing the Si particles with the carbon layer not only buffers the volume expansion but also realizes the formation of a stable SEI film on the surface of a carbon layer, preventing continuous consumption of Li + . , In certain instances, the electrochemical performance of Si-based anodes can be further enhanced by either employing multilayer carbon coating or introducing inorganic semiconductors within the carbon layer; − however, this also adds complexity to the preparation process of the anode.…”