Carbon coating on metal oxide materials for electrochemical energy storage

Abstract

During the past decades, nano-structured metal oxide electrode materials have received growing attention due to their low development cost and high theoretical specific capacity, accordingly, quite a lot of metal oxide electrode materials are being used in electrochemical energy storage devices. However, the further development was limited by the relatively low electrical conductivity and the volume expansion during electrochemical reactions. Thus, many approaches have been proposed to obtain high-efficiency metal oxide electrode materials, such as designing nanomaterials with ideal morphology and high specific surface area, optimizing with carbon-based materials (such as graphene and glucose) to prepare nanocomposites, combining with conductive substrates to enhance the conductivity of electrodes, etc. Owning to the advantages of low cost and high chemical stability of carbon materials, core–shell structure formed by carbon-coated metal oxides is considered to be a promising solution to solve these problems. Therefore, this review mainly focuses on recent research advances in the field of carbon-coated metal oxides for energy storage, summarizing the advantages and disadvantages of common metal oxides and different types of carbon sources, and proposing methods to optimize the material properties in terms of structure and morphology, carbon layer thickness, coating method, specific surface area and pore size distribution, as well as improving electrical conductivity. In addition, the double or multi-layer coating strategy is also a reflection of the continuous development of carbon coating method. Hopefully, this rereview may provide a new direction for the renewal and development of future energy storage electrode materials.

Soft Carbon Integration for Prolonging the Cycle Life of LiNi0.5Mn1.5O4 Cathode

“…In other words, it is the carbon coating which turned the commercialization of LiFePO 4 into a revolutionary success . However, the same process never gained interest for the oxide materials . On the other hand, the spinel LNMO suffers from complicated limitations including low electronic conductivity and parasitic surface reactions. , The integration of soft carbon simultaneously takes care of both and improves the electrochemical performances.…”

“…Moreover, the chemical formation of carbon coating from its precursor on the LNMO surface is challenging due to the possibility of carbothermal reduction of the metal oxide core. 58 Carbonization at lower temperatures yields an imperfect carbon structure, whereas higher temperatures may affect the formation of the crystal structure. Therefore, synthetic optimization is a tedious task.…”

“…Therefore, the improvements are either marginal or perform poorly during long-term cycling at a standard current rate. Moreover, the chemical formation of carbon coating from its precursor on the LNMO surface is challenging due to the possibility of carbothermal reduction of the metal oxide core . Carbonization at lower temperatures yields an imperfect carbon structure, whereas higher temperatures may affect the formation of the crystal structure.…”

Flexible N-Doped Graphene Electrodes Fabricated via Rapid Direct Hot Stamping for Microsupercapacitors

“…With the evolution of portable and wearable electronics, attention is being paid to lightweight, flexible, high-performance, and safe energy storage devices. , Being a remarkable electrochemical energy storage device in integrated electronics, planar flexible microsupercapacitors (MSCs) are undergoing continuous advancements to achieve rapid charge/discharge rates, high power density, exceptional stability, and enhanced mechanical flexibility . Extensive research endeavors have been dedicated to exploring and developing diverse materials as in-plane electrodes for MSCs, encompassing the utilization of carbon-based materials, , conducting polymers, and metal oxides . Novel advanced materials, for instance, MXenes, metal–organic frameworks, and black phosphorus, have emerged as promising candidates for constructing MSC electrodes.…”

“…3 Extensive research endeavors have been dedicated to exploring and developing diverse materials as inplane electrodes for MSCs, encompassing the utilization of carbon-based materials, 4,5 conducting polymers, 6 and metal oxides. 7 Novel advanced materials, for instance, MXenes, 8 metal−organic frameworks, 9 and black phosphorus, 10 have emerged as promising candidates for constructing MSC electrodes. Apart from electrode materials, the scalable production of flexible MSCs heavily relies on the development of suitable manufacturing methods.…”