Energy Storage Performance Enhancement by Surface Engineering of Electrode Materials

Abstract

transportation, limiting the rate capability and power density of LIBs and SIBs. In addition, due to the larger size of Na + than Li + , the challenges of SIBs are more signifi cant, including poor cycling stability, low columbic effi ciency, and insuffi cient power capability. On these regards, surface engineering is an essential research issue. From 1990s, considerable efforts have been devoted to the nanosynthesis of electrode materials, boosting the fast development of new electrode materials for high-performance electrochemical energy storage (EES) devices. [4][5][6] An electrode with surface engineered nanostructure can render benefi ts to its electrochemical properties, including (i) abundant active sites and electrode/electrolyte contact area, (ii) enhanced electrical conductivity and charge collection effi ciency, (iii) shortened ion diffusion paths and higher ionic conductivity, (iv) better mechanical alleviation for insertion/de-insertion strain. [ 7 ] However, nanoscaling is a "double-edged sword"; It cannot fulfi ll all the rigorous requirements of LIBs and SIBs. Parasitic reactions may occur on the exposed surfaces of electrode materials, such as the solubility of intermediated products, the formation of unstable solid electrolyte interface (SEI) fi lms, and the decomposition of electrolyte. These will lead to deformation of electrode structure and subsequently the capacity decay upon long cycles. To tackle these issues, a rational design of nanostructures and surface engineering are in the ascendant. [ 8,9 ] In view of the growing number of surface engineering strategies that have employed successfully for electrodes of various types of energy storage devices (e.g., batteries, photoelectrochemical cells, and supercapacitors), in this report, we will highlight the recent progress specifi cally in LIBs and SIBs. We start with a general summary of nanostructured electrode confi gurations and surface coating methods, and then elaborate the basic effects of nanoscale size, pore, and morphology. Our main discussion will be put on the effects of surface engineering on suppressing secondary reaction and SEI fi lm, buffering for volume expansion, electrical and ionic conductivity enhancement for LIBs and SIBs. At the end, we will provide an overall conclusion and our own perspective. A General Summary of Surface Engineering StrategiesGenerally, the concept of surface engineering can be classifi ed into two main categories (see Figure 1 ): (i) intrinsic nanostructures with high surface areas and (ii) hybridization with Surface engineering of electrode materials to yield favorable electrochemical performance is a hot spot of current research in the energy storage area. Here, this Report highlights recent progress in rational surface engineering strategies in association with their effects on the electrochemical properties. The electrochemical performance enhancement due to both intrinsic nanostructuring and hybridization with surface functional species is elaborated. The focus here is lithium and sodium ion b...

Electrochromic Battery Displays with Energy Retrieval Functions Using Solution‐Processable Colloidal Vanadium Oxide Nanoparticles

“…This indicates that the round-trip netenergy consumption is only 79.5 mWh g −1 (170.3 mWh m −2 ). [32,33] To shed light on the operation of the Zn-V 3 O 7 electrochromic battery display, ex situ XPS measurements were carried out to evaluate the valence state of the V accompanied by Zn 2+ insertion/extraction. There is only one process consuming energy in the electrochromic battery display, while the traditional electrochromic display consumes energy in both coloration and bleaching processes.…”

Surface/Interface Structure Degradation of Ni‐Rich Layered Oxide Cathodes toward Lithium‐Ion Batteries: Fundamental Mechanisms and Remedying Strategies

“…With all the considerations above in mind, it can be obviously found that the surface/interface structure and chemistry of the Ni‐rich cathodes play a vital role in determining the electrochemical properties and industrial processability. Therefore, within the past decades, worldwide efforts focusing on the surface/interface modifications have been devoted to regulate the chemical and/or physical properties of the cathodes . More significantly, microstructure degradation during accelerated calendar aging structural evolution under high voltages and elevated temperature conditions and oxygen release phenomenon as well as several new insights into the cation disorder concerning the Ni‐rich cathodes have been lately uncovered by various means.…”

“…Therefore, within the past decades, worldwide efforts focusing on the surface/interface modifications have been devoted to regulate the chemical and/or physical properties of the cathodes. [35][36][37][38] More significantly, microstructure degradation during accelerated calendar aging [39,40] structural evolution under high voltages [41][42][43][44][45][46] and elevated temperature conditions [41,[47][48][49][50] and oxygen release phenomenon [1,46,[51][52][53][54] as well as several new insights into the cation disorder [55][56][57] concerning the Ni-rich cathodes have been lately uncovered by various means. A comprehensive summary of the advancements in the field of Ni-rich cathodes has been reported recently, [2,6,12,14,16,36,[58][59][60][61][62] but an overview of the fundamental origins governing these surface/interface behaviors has yet to be completely realized.…”

Novel MOF shell-derived surface modification of Li-rich layered oxide cathode for enhanced lithium storage

“…For instance, Zheng et al [35] designed a surface modification with LiFePO 4 , which provides lithium ion and charge transport channels as well as protects the surface structure from side reactions at the electrode/electrolyte interface. Moreover, surface modification via carbon coating has been widely applied to cathode materials (e.g., LiFePO 4 [36], Li 2 MnO 4 [37], and LiNi 1/3 Mn 1/3 Co 1/3 O 2 [38]) to provide enhanced structure stability and high electronic conductivity, thereby improving the rate capability and cycling performance [39]. However, this carbon coating strategy is rarely applied to modify LLO.…”