Silica‐Mediated Formation of Nickel Sulfide Nanosheets on CNT Films for Versatile Energy Storage

Abstract

An effective, nondestructive, and universal strategy to homogeneously modify freestanding carbon nanotube (CNT) films with various active species is essential to achieve functional electrodes for flexible electrochemical energy storage, which is challenging and has attracted considerable research interest. In this work, a generalizable concept, to utilize silicon oxide as the intermediate to uniformly decorate various metal sulfide nanostructures throughout CNT films is reported. Taking nickel sulfide nanosheet/CNT (NS/CNT) films, in which the NS nanosheets are homogeneously attached on the intact few‐walled CNTs, as an example, the sheet‐like NS provides sufficient active sites for redox reactions and the CNT network acts as an efficient electron highway, maintaining the structural integrity of the composite and also buffering volume changes. These merits enable NS/CNT films to meet the requirements of versatile energy storage applications. When used for supercapacitors, a high specific capacitance (2699.7 F g−1/10 A g−1), outstanding rate performance at extremely high rates (1527 F g−1/250 A g−1), remarkable cycling stability, and excellent flexibility can be achieved, among the best performance so far. Moreover, it also delivers excellent performance in the storage of Li and Na ions, meaning it is also potentially suitable for Li/Na ion batteries.

Ultrathin Ni Co -silicate nanosheets natively anchored on CNTs films for flexible lithium ion batteries

“…The flexible NC/SC hybrid film was fabricated through a silicamediated conversion process [41]. First, continuous and free-standing SiO x /CNT hybrid films were prepared by the modified chemical vapor deposition (CVD) method in a vertical tube furnace (Fig.…”

“…Ni 2p 3/2 peaks at 857.3 eV can be attributed to Ni silicates with different oxidation states as a result of the interaction with CNTs [28,33]. Due to the diversity of the valence states of the metal species, the conductivity of the Ni x Co y -silicate nanosheets can be improved by establishing a low activation energy hopping channel between the metal ions, thus promoting the electrochemical process of materials [41,47,48].…”

Progress in supercapacitors: roles of two dimensional nanotubular materials

“…412 Some of the recent developments in high-performance supercapacitors using nanotubular networks have opened a new avenue for exploring techniques, specically electrode characterization and modulations, to achieve high power density, capacity retention, and good cyclability. 215,216,[223][224][225][226][227]264,386, Although the advancements and implementations of nanotubular networks in supercapacitors have signicantly achieved better storage capabilities and performance, tailoring and optimization of materials are still in a developmental phase where cost-effectiveness and good performance are some of the key concerns in practical applicability. In an attempt to develop a combination of high power and energy densities, hybrid technology is one of the challenging aspects.…”

“…The 1 st category [191][192][193][194][195][196][197] consists of supercapacitors with low energy density (0-10 W h kg À1 ) and specic capacitance below 100 F g À1 , the 2 nd category 54,56,196,[198][199][200][201][202][203][204][205][206][207][208] consists of supercapacitors with energy density in the range of 10-40 W h kg À1 , the 3 rd category [209][210][211] consists of supercapacitors with an energy density range of 70-100 W h kg À1 , and the 4 th category [212][213][214] consists of supercapacitors with energy density from 140-160 W h kg À1 and the description of the materials is tabulated in Table 3. Recent progress in CNT based high-performance supercapacitors has been immensely investigated using various techniques [215][216][217][218][219][220][221][222][223][224][225][226][227][228][229][230] and more systematic investigations ar...…”

Recent Advances in Carbon‐Based Bifunctional Oxygen Catalysts for Zinc‐Air Batteries

“…However, Li‐ion batteries face a number of challenges, especially the safety issues and the uprising cost of battery materials . To avoid these problems, the development of alternative electrochemical energy storage and conversion technologies (e. g., sodium‐ion batteries, lithium‐metal batteries, lithium and nonlithium metal‐sulfur batteries, fuel cells, and metal‐air batteries) has led to intensive research activity. Among them, metal‐air batteries have gained special research interests due to their very high energy density, low cost, and environment‐friendly operation.…”