A Novel Perovskite Electron–Ion Conductive Coating to Simultaneously Enhance Cycling Stability and Rate Capability of Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ Cathode Material for Lithium‐Ion Batteries

Abstract

Poor cycling stability and rate capability are two key issues needing to be solved for Li‐ and Mn‐rich oxide cathode material for lithium‐ion batteries (LIBs). Herein, a novel perovskite electron–ion mixed conductor Nd0.6Sr0.4CoO3 (NSCO) is used as the coating layer on Li1.2Ni0.13Co0.13Mn0.54O2 (LNCMO) to simultaneously enhance its cycling stability and rate capability. By coating 3 wt% NSCO, LNCMO–3NSCO exhibits an optimal cycling performance with a capacity retention of 99% at 0.1C (1C = 200 mA g−1) after 60 cycles, 91% at 1C after 300 cycles, and 54% at 20C after 1000 cycles, much better than 78%, 63%, and 3% of LNCMO, respectively. Even at a high charge and discharge rate of 50C, LNCMO–3NSCO exhibits a discharge capacity of 53 mAh g−1 and a mid‐point discharge voltage of 2.88 V, much higher than those of LNCMO (24 mA h g−1 and 2.40 V, respectively). Benefiting from the high electronic conductivity (1.46 S cm−1) and ionic conductivity (1.48 × 10−7 S cm−1), NSCO coating not only suppresses transition metals dissolution and structure transformation, but also significantly enhances electronic conductivity and Li+ diffusion coefficient of LNCMO by an order of magnitude.

Bichannel design inspired by membrane pump: a rate booster for the conversion-type anode of sodium-ion battery

“…It is acknowledged that the rate capability is determined by both electron and ion transport. 10–12 The limiting process for highly conductive hard carbon is ion transport. 13 Drawing lessons from hard carbon, rapid ion transport channel in an anode material is essential for improving rate capability.…”

Accurate Calculation of Solid-State Li+ Diffusion Coefficient and Kinetic Activation Energies for an Artificial Graphite Anode

“…[15][16][17][18] However, it is a challenge to prepare composite electrodes with thinner and minimal active material as far as possible, so characterizing them by various electroanalytical techniques is crucial. Cyclic voltammetry (CV), 19,20 electrochemical impedance spectroscopy (EIS) 21,22 and galvanostatic intermittent titration technique (GITT) 23,24 have been widely employed to explore the kinetics of Li + insertion/extraction in batteries. 25,26 At higher sweep rates, the CV curve deviates from diffusion-controlled electrochemical behavior due to the large ohmic potential drop caused by a rapid increase in current.…”

New Emerging Fast Charging Microscale Electrode Materials

“…[82] For example, the metallic NiP coating on the LiFePO 4 cathode not only can increase conductivity but also can promote morphological and structural stability upon cycling. [83] Except for the aforementioned single conductive coating materials, various fast ionic conductors and electron-ion mixed conductors, such as Nd 0.6 Sr 0.4 CoO 3 , [84] LiNbO 3 , [85] LiAlF 4 , [86] have been applied as surface coating materials to facilitate the migration of ion and electron.…”