High-Voltage “Single-Crystal” Cathode Materials for Lithium-Ion Batteries

Abstract

To boost the use of electronic devices and driving mileage of electric vehicles, it is urgent to develop lithium-ion batteries (LIBs) with higher energy density and longer life. High-voltage and high-capacity cathode materials, such as LiCoO 2 , LiNi 0.5 Mn 1.5 O 4 , Ni-rich layered oxides, and lithium-rich layered oxides, are critically important for LIBs to obtain high energy density. Among various forms of these materials, "single-crystal" cathodes (SCCs) have shown many advantages over other forms for industrial applications, including good crystallinity, high mechanical strength, high reaction homogeneity, small specific surface area, excellent structural stability, and high thermal stability, which can noticeably improve the cycling performance and safety of SCCbased batteries. Therefore, SCCs have received wide attention from academic to industrial communities and have been applied to the liquid-based and solid-state batteries in recent years. In this paper, the advantages, progress, and challenges of SCCs for highvoltage cathode materials are reviewed. Moreover, we summarize the efforts for improving the electrochemical performance of SCCs, intending to provide insights into the development of high-performance cathodes for practical LIBs.

Stabilizing electrode–electrolyte interfaces to realize high-voltage Li||LiCoO2 batteries by a sulfonamide-based electrolyte

“…This result suggests that the SCC behavior usually observed in polycrystalline NMC cathodes 39 is also present in the deep-cycled LCO cathode with a single-crystalline microstructure, which is usually considered not to crack easily. 49 Similar cracking behavior was previously reported in deep-cycled single-crystalline NMC 50 and LCO 7,24 cathodes. Considering the high catalytic capability of the LCO surface that may promote more intensive side reactions, a ''good'' electrolyte or proper surface modification that can passivate the surface cracks and thus suppress the SCC, is required for 44.5 V Li LCO.…”

Restraining Oxygen Release and Suppressing Structure Distortion in Single‐Crystal Li‐Rich Layered Cathode Materials

“…Intriguingly, SC sample showed the superior rate performance at both low and high current density, which is totally different from rate results in previous studies. [ 15a ] Therefore, the galvanostatic intermittent titration technique tests were performed to calculate Li + diffusion coefficient ( D Li + ) and study the kinetics behaviors of both PC‐LLNMO and SC‐LLNMO electrodes (Figure S4, Supporting Information), [ 15b,c ] in which SC sample harvested the higher D Li + values in both TM‐based and oxygen‐related regions. It proved the superior rate performances can be obtained within SC sample during both charging and discharging processes compared with PC sample.…”

A Review of Degradation Mechanisms and Recent Achievements for Ni‐Rich Cathode‐Based Li‐Ion Batteries

“…A direct strategy to reduce grain boundary stress is to fabricate single‐crystal cathode particles. [ 118,119 ] Advanced mechanical strength and more homogeneous electrochemical reactions can be achieved due to the high crystallinity and isotropy orientation of single‐crystal cathode materials.…”