Search

The development of high‐performance anode materials for potassium‐based energy storage devices with long‐term cyclability requires combined innovations from rational material design to electrolyte optimization. A three‐dimensional K+‐pre‐intercalated Ti3C2Tx MXene with enlarged interlayer distance was constructed for efficient electrochemical potassium‐ion storage. We found that the optimized solvation structure of the concentrated ether‐based electrolyte leads to the formation of a thin and inorganic‐rich solid electrolyte interphase (SEI) on the K+‐pre‐intercalated Ti3C2Tx electrode, which is beneficial for interfacial stability and reaction kinetics. As a proof of concept, 3D K+‐Ti3C2Tx//activated carbon (AC) potassium‐ion hybrid capacitors (PIHCs) were assembled, which exhibited promising electrochemical performances. These results highlight the significant roles of both rational structure design and electrolyte optimization for highly reactive MXene‐based anode materials in energy storage devices. [ABSTRACT FROM AUTHOR]

MXenes have been considered as a promising electrode material for Na+ or K+ storage due to their high conductivity, large specific surface area and unique 2D layered structure. However, their tendency to restacking limits the penetration of electrolyte, resulting in poor energy storage capacity. In efforts to overcome this obstacle and take full advantage of Ti 3 C 2 T x MXene, herein, Ti 3 C 2 T x MXene/CNT hybrid has been rationally fabricated as the anode for high-performance sodium- and potassium-ion storage through a surfactant-free assembly strategy assisted by hydrochloric acid (HCl). The HCl-assisted assembly can realize the assembly of Ti 3 C 2 T x MXene and CNT on the nanoscale to make full use of the advantages of CNT as a spacer. Moreover, highly conductive CNT can also provide more diffusion paths for electrons and sodium/potassium ions. Benefiting from the synergistic effect between CNT and Ti 3 C 2 T x flakes, the Ti 3 C 2 T x /CNT hybrid has exhibited excellent electrochemical properties for sodium- and potassium-ion storage. It is worth emphasizing that the Ti 3 C 2 T x /CNT electrode also has superior rate capability, which outperforms that of most reported literatures. This work proposes a new strategy for introducing CNT between MXene layers, which could be expected to be an effective strategy to exert the attracting surface functionality for target applications. [Display omitted] ● Ti 3 C 2 T x /CNT hybrid has been fabricated by a surfactant-free assembly strategy assisted by hydrochloric acid (HCl). ● The HCl-assisted assembly realizes the assembly of Ti 3 C 2 T x and CNT on the nanoscale without contaminating the surface of Ti 3 C 2 T x. ● Ti 3 C 2 T x /CNT hybrids exhibit superior rate capability outperforming that of most reported literatures. [ABSTRACT FROM AUTHOR]

SnSe/r-GO composite with SnSe nanorods anchoring on the r-GO surface by Sn–O–C and Sn–C bonds was prepared successfully by in-situ selenization of SnO 2 /r-GO precursor. When employed as lithium ion battery anode, SnSe/r-GO exhibits more superior electrochemical performance than SnO 2 /r-GO composite. [Display omitted] • SnSe/r-GO is prepared by in-situ selenization transformation from SnO 2 /r-GO. • SnSe nanorods are anchored on r-GO surface homogeneously via the Sn–O–C and Sn–C bonds. • The SnSe/r-GO demonstrates much better cycling and rate performance than SnO 2 /r-GO. SnSe is regarded as one of the promising anodes for the next-generation lithium ion batteries (LIBs) due to high theoretical capacity and good conductivity. Herein, SnSe/r-GO composite is synthesized by in-situ selenization transformation from SnO 2 /r-GO and it displays the structure that SnSe nanorods are dispersed on the surface of r-GO homogeneously via the Sn–O–C and Sn–C bonds. The chemically bonded SnSe/r-GO demonstrates much better cycling and rate performance than SnO 2 /r-GO when used as LIBs anode. It can afford a high discharge capacity of 1196.4 mAh·g−1 in the first cycle and maintained at 606.6 mAh·g−1 after 100 cycles. Even at high current density of 1000 mA·g−1, the specific capacity of SnSe/r-GO can reach to 423.8 mAh·g−1. This work provides an in situ synthesis strategy for high-performance tin-based material in the application of energy storage. [ABSTRACT FROM AUTHOR]