Multistage Li_1.2Ni_0.2Mn_0.6O₂ Micro‐architecture towards High‐Performance Cathode Materials for Lithium‐Ion Batteries

Abstract

Constructing hierarchical‐architecture primary nanoparticles that assemble with secondary micro‐architectures is very effective to achieve high‐performance cathode materials for lithium‐ion batteries (LIBs). In this work, well‐crystallized lithium‐rich layered oxide cathode materials Li1.2Ni0.2Mn0.6O2 (LNMO) with a micro‐architecture was successfully synthesized. The preparation process is divided into two steps: the solvothermal process synthesizes the precursor Ni0.25Mn0.75CO3 (NMCO) and gradient temperature calcination is used to prepare the primary nanoparticles that agglomerate into hierarchical microspheres for final‐product LNMO. The as‐prepared material was used as cathode materials for LIBs, which exhibit good cycle life and excellent rate performances. The material retains a fairly high discharge capacity of approximately 180 mAh g−1 after 180 cycles at the 2C rate (1C=200 mA g−1). Even after a 50‐fold (5C/0.1C) increase, a discharge capacity 61.4 % (153.8 mAh g−1) of the capacity at 0.1C (ca. 249.1 mAh g−1) could be retained. This superior cycle life and rate performance are attributed to the merits of the hierarchical nano‐/microsphere structures.

MnO/Mn2O3 Nanowires Coated by Porous N-Doped Carbon for Long-Cycle and High-Rate Lithium-Ion Batteries

“…They are always used to quantitatively assess the electrochemical characteristics, the charge transfer resistance, and the change of Li + diffusion at different phases. The equation D Li + = R 2 T 2 /(2 A 2 n 4 F 4 C 2 σ 2 ) is used for calculating the diffusion coefficient value of lithium ions diffused into the electrode materials . The parameter values in the equation are listed in Table S1.…”

“…The equation D Li + = R 2 T 2 /(2A 2 n 4 F 4 C 2 σ 2 ) is used for calculating the diffusion coefficient value of lithium ions diffused into the electrode materials. 62 The parameter values in the equation are listed in Table S1. We have listed the calculated D Li + in Tables S2 and S3.…”

Uniform Na+ Doping‐Induced Defects in Li‐ and Mn‐Rich Cathodes for High‐Performance Lithium‐Ion Batteries

“…This phenomenon is also due to the decreased amount of the formed Li 2 CO 3 over the prolonged cycles which is verified in Figure S8, Supporting Information. [49] However, unlike the conventional tendency of a tardily capacity decay happened to pristineand Na/SDS-LMR, there is a distinct sharp capacity decrease in the prolonged cycle of Na-LMR and always occur around 120 cycles; the same case is also found in the specific discharge energy density ( Figure S13, Supporting Information). As shown in Figure S9, Supporting Information, the problem of voltage fading is also suppressed and agrees with the curves of dQ/dV ( Figure S10, Supporting Information) and the reduction peaks marked by pink arrows in Figure 3a-c, especially after 120 cycles.…”

“…Compared to pristine‐LMR, the cation uniformly doped electrode, Na/SDS‐LMR, gets a smaller increase of impedance after cycling. Also, the D Li s of electrodes after 50 cycles are summarized in Table S2, Supporting Information, and the Na/SDS‐LMR exhibits a better charge–ion transfer kinetics, which is significantly promoted from 1.556 × 10 −16 to 3.391 × 10 −16 cm 2 s −1 , originating from the increased interplanar spacing of c ‐axis and the boosted diffusion of conducting ions . However, unlike the conventional tendency of a tardily capacity decay happened to pristine‐ and Na/SDS‐LMR, there is a distinct sharp capacity decrease in the prolonged cycle of Na‐LMR and always occur around 120 cycles; the same case is also found in the specific discharge energy density (Figure S13, Supporting Information).…”

General Airbrush‐Spraying/Electrospinning Strategy for Ultrahigh Areal‐Capacity LiFePO4‐Based Cathodes

“…Over the past decades, the lithium‐ion batteries (LIBs) have attracted great attention and been widely applied in grid‐scale energy storage systems (ESSs), electric vehicles (EVs) and consumer electronics . To achieve high energy and power density LIBs, the designing and fabricating electrodes are essential attempts .…”