Precise Surface Engineering of Cathode Materials for Improved Stability of Lithium‐Ion Batteries

Abstract

As lithium‐ion batteries continue to climb to even higher energy density, they meanwhile cause serious concerns on their stability and reliability during operation. To make sure the electrode materials, particularly cathode materials, are stable upon extended cycles, surface modification becomes indispensable to minimize the undesirable side reaction at the electrolyte–cathode interface, which is known as a critical factor to jeopardizing the electrode performance. This Review is targeted at a precise surface control of cathode materials with focus on the synthetic strategies suitable for a maximized surface protection ensured by a uniform and conformal surface coating. Detailed discussions are taken on the formation mechanism of the designated surface species achieved by either wet‐chemistry routes or instrumental ones, with attention to the optimized electrochemical performance as a result of the surface control, accordingly drawing a clear image to describe the synthesis–structure–performance relationship to facilitate further understanding of functional electrode materials. Finally, perspectives regarding the most promising and/or most urgent developments for the surface control of high‐energy cathode materials are provided.

A review on the stability and surface modification of layered transition-metal oxide cathodes

“…There are a few review papers summarizing the issues and mitigation approaches for Ni-rich layered TM oxides or Li-/Mn-rich layered TM oxides in the past years [14,17,18,[63][64][65][66][67]. We provide in this review a more comprehensive account of the strategies employed in a unified manner for both Ni-rich and Li-/Mn-rich layered TM oxides, which are promising cathode candidates for LIBs and Li metal batteries, considering the work during the past decade.…”

The Functions and Applications of Fluorinated Interface Engineering in Li‐Based Secondary Batteries

“…The wet chemistry‐based methods are extensively used to synthesize designated surface coating layers through chemical reactions in aqueous/nonaqueous solutions. Such treatment routes are facile and scalable for applying in manufacture, which usually follows several steps: [ 26 ] 1) preparing organic/aqueous precursor solution containing metal salt; 2) immersing the “nuclear” material into the solution and fully dispersed to form a uniform sol system; 3) adding precipitant and changing the solution environment to precipitate the desired “shell” material. However, in most cases, the precipitation rate is too fast to induce a homogenous nucleation, so that a reagent or operation capable of finely tuning the precipitation condition is quite needed to make reactions controllable.…”

“…[22,23] Surface modification is not only the core treatment process of positive and negative electrode materials but also an effective method to establish functional interfacial layers. [24][25][26] Such technology needs our basic understanding of interface evolution mechanism, ion transport chemistry, compositional structure along with recognition of the function of each component. However, this is exactly what is currently missing on account of existing knowledge and characterization tools.…”

Nanoengineered Organic Electrodes for Highly Durable and Ultrafast Cycling of Organic Sodium‐Ion Batteries

“…Conventional metal oxide coating methods (solid-state, sol-gel, and hydrothermal) involve the use of high-temperature processes that are not suitable for organic electrodes owing to their low thermal stability. [35] Furthermore, uniform, precise, and ultrathin coatings cannot be realized with conventional techniques. Recently, atomic layer deposition (ALD) has emerged as an attractive tool for obtaining ultrathin (Å-level) metal oxide coatings via gas phase reactions at a very low temperature.…”