Polymer-Derived Ceramic Functionalized MoS2 Composite Paper as a Stable Lithium-Ion Battery Electrode

Sun

et al. 2016

Adv Funct Materials

182

7479wileyonlinelibrary.com sodium resources, SIBs are more attractive for grid distribution systems. To date, the study of cathode materials for SIBs, such as various layered oxides, [6][7][8][9][10] polyanionic compounds, [11][12][13][14] and Prussian-blue-based materials, [15][16][17] is very progressive. [ 18 ] Nevertheless, developing durable and high-capacity anode materials is still a major issue. [ 19 ] Even though tremendous efforts have been devoted to developing anode materials for SIBs, including carbonaceous materials, [20][21][22][23][24][25] transition metal oxides, [26][27][28][29][30] intermetallic compounds, [31][32][33][34] etc., most of these reported materials still exhibit low reversible capacities or poor cycle life. Notably, their sodium storage performance is very inferior as compared with lithium storage, which might be induced by the sluggish sodiation/desodiation reaction kinetics. Therefore, it is highly desirable and greatly challenging to develop a robust anode material with high specifi c capacity and good cycling stability for sodium storage. Similar to transition metal oxides, most metal sulfi des are capable of storing lithium or sodium via the conversion reaction or a combined conversion-alloying reaction, and they possess promisingly high theoretical capacities. [35][36][37][38][39] Basically, metal sulfi des exhibit higher electrical conductivity than metal oxides, and this unique property is critical for accelerating reaction kinetics, especially for sodiation/desodiation reactions. [ 40,41 ] In terms of lithium storage, much encouraging progress on metal sulfi de anodes has been reported. [42][43][44] Recently, several metal sulfi des (SnS 2 , [ 35,[45][46][47] MoS 2 , [48][49][50] CoS x ( x = 1,2), [ 36,[51][52][53] and FeS 2[ 54 ] ) have been experimentally investigated as anode materials for SIBs and have shown very impressive sodium storage performances. It should also be mentioned, however, that metal sulfi des still suffer from huge volume changes caused by the conversion reaction during the lithiation/delithiation or sodiation/desodiation reactions. [55][56][57] This would lead to electrode cracking, pulverization, and disconnection from current collectors over the course of cycling, eventually resulting in rapid capacity fading. To mitigate the rapid capacity fading induced by the large volume expansion, developing hierarchical and hollow structures, with nanosized building blocks, a porous shell, and an interior cavity has been demonstrated to be a very effective approach. [ 40,[58][59][60][61] On the one hand, the porous shells and hollow structures provide enough spaces to buffer the strain induced by the volumetric expansion/shrinkage during repeated insertion/extraction of Li + or Na + . In addition, the hollow spheres are loosely stacked, Sodium-ion batteries (SIBs) are considered as promising alternatives to lithium-ion batteries (LIBs) for energy storage due to the abundance of sodium, especially for grid distribution systems. The practical implementation of ...

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Engineering Hierarchical Hollow Nickel Sulfide Spheres for High‐Performance Sodium Storage

Sun

et al. 2016

Adv Funct Materials

182

“…The TiO 2 ⊂NPCTO/NaK has the highest ICE largely due to the liquid–liquid connection with the lower electrochemical resistance and faster ion diffusion (the detailed explanation in the following discussion). Considering the above analyses and results, the irreversible reactions mainly occur in the first cycle and form stable SEI film . The rising of CE indicates the gradual formation of stable SEI on the TiO 2 ⊂NPCTO electrode surface .…”

mentioning

confidence: 83%

New Insights into the Electrochemistry Superiority of Liquid Na–K Alloy in Metal Batteries

Huang

Feng

et al. 2019

Small

The significant issues with alkali metal batteries arise from their poor electrochemical properties and safety problems, limiting their applications. Herein, TiO2 nanoparticles embedded into N‐doped porous carbon truncated ocatahedra (TiO2⊂NPCTO) are engineered as a cathode material with different metal anodes, including solid Na or K and liquid Na–K alloy. Electrochemical performance and kinetics are systematically analyzed, with the aim to determine detailed electrochemistry. By using a galvanostatic intermittent titration technique, TiO2⊂NPCTO/NaK shows faster diffusion of metal ions in insertion and extraction processes than that of Na‐ions and K‐ions in solid Na and K. The lower reaction resistance of liquid Na–K alloy electrode is also examined. The higher b‐value of TiO2⊂NPCTO/NaK confirms that the reaction kinetics are promoted by the surface‐induced capacitive behavior, favorable for high rate performance. This superiority highly pertains to the distinct liquid−liquid junction between the electrolyte and electrode, and the prohibition of metal dendrite growth, substantiated by symmetric cell testing, which provides a robust and homogeneous interface more stable than the traditional solid−liquid one. Hence, the liquid Na–K alloy‐based battery exhibits to better cyclablity with higher capacity, rate capability, and initial coulombic efficiency than solid Na and K batteries.

“…However, due to the lack of defect tolerance, catastrophic failures may occur when ceramics were subject to machining processes 9 . The polymer to ceramic transformation route, denoted as polymer‐derived ceramic (PDC), is one of the key technique breakthroughs in ceramic manufacturing field; the liquid polymer precursors can provide ceramics with a designed chemical composition and prefect workability 10–15 . Many scholars have therefore explored the application of PDC in sensor manufacture.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of high‐fracture‐strength and gas‐tightness PDC films via PIP process for pressure sensor application

Liu

et al. 2020

J Am Ceram Soc

High‐fracture‐strength and high‐gas‐tightness thin‐film gas‐pressure sensors were fabricated using a silicon oxycarbonitride polymer‐derived‐ceramic (SiCNO‐PDC) material via a multiple polymer‐infiltration‐pyrolysis (PIP) process. To obtain dense SiCNO ceramic films, two types of liquid polyvinylsilazane (PVSZ) precursors were chosen; a high‐ceramic‐yield precursor with high viscosity (PVSZ‐1) was designed to construct the skeleton of ceramic film, whereas a relatively high‐ceramic‐yield precursor with low viscosity (PVSZ‐2) was designed to infiltrate in ceramic defects. The results confirmed that the PVSZ‐2 can effectively fill both intergranular and intragranular defects of ceramic films pyrolyzed by the PVSZ‐1, and produce the sponge‐like structures with nanosized pores. Although the density of the ceramic films only increased by 2.2%‐5.2% after PIP process, the gas tightness was fundamentally improved, and all ceramic films after PIP process could keep gas‐tight condition without loss of pressure after 72 hours. Similarly, the fracture strengths of the ceramic films after PIP cycles have also been improved, and the value could reach 108 MPa after only three PIP cycles. In addition, because a linear relationship among the load, resonant frequency, and deflection was detected in our ceramic films, the wireless passive gas‐pressure sensors with high‐sensitivity and high‐temperature resistance have been fabricated. It strongly indicates that the ceramic films obtained by our PIP process have real potential to be used as thin‐film gas‐pressure sensing elements in high‐temperature and high‐pressure fields.