Lithiation Mechanism Change Driven by Thermally Induced Grain Fining and Its Impact on the Performance of LiMn₂O₄ in Lithium‐Ion Batteries

Abstract

The nature of precursors employed in the synthesis of lithium‐ion battery cathode materials is a crucial performance‐dictating factor. Therefore, it is of great importance to establish a way to manipulate the precursor and seek a comprehensive understanding of its influence on the electrochemical behavior of a targeted electrode material. A thermal route is herein demonstrated for the synthesis of lithium‐excess LiMn2O4 (LMO) by exploiting an intriguing thermal phenomenon, thermally induced grain fining, and sheds light on how it affects the mechanism and kinetics of lithiation, and, furthermore, the electrochemical behavior of LMO. Detailed insights into the lithiation mechanism and kinetics reveal that the use of a finely grained, porous Mn3O4, which possesses an open crystal structure, is a key to the success of incorporating excess Li. In addition, this in‐depth electrochemical investigation verifies a very recent theoretical prediction of faster Li diffusion kinetics enabled by excess Li.

Ternary Si–SiO–Al Composite Films as High-Performance Anodes for Lithium-Ion Batteries

“…To further assess the commercial viability of this Si–SiO–Al film anode, we assembled this film anode with a LiMn 2 O 4 cathode into a complete battery to test its full cell performance, where the mass loading of the Si–SiO–Al film electrode is 0.2 mg cm –2 and that of LiMn 2 O 4 electrode is 4.6 mg cm –2 . − The current density used for the full cell is 110 mA g –1 . The charge/discharge curves of the first three cycles for the soft packed full battery are shown in Figure a.…”

Carbon-Doped TiNb2O7 Suppresses Amorphization-Induced Capacity Fading

“…However, it is obvious that the contribution of the bi-phase transition to the capacity is the most minimized in TNO-600 compared to other counterparts because this bi-phase transition gradually appeared for TNO samples calcined at higher temperatures. Our speculation was supported when we further analyzed the CV responses based on the power-law relationship where i p is the peak current (A), a and b are the parameters, and ν is the potential scan rate (mV s –1 ). If the value of b is 1, then the charge transfer process is capacitive, and if it is 0.5, then the process is diffusion-limited.…”

New Class of Titanium Niobium Oxide for a Li-Ion Host: TiNbO4 with Purely Single-Phase Lithium Intercalation

“…All the measured impedance spectra showed a single semicircle followed by the capacitive tail in the Nyquist plot (Figures S13 and 14). The semicircle was attributed to the charge transfer resistance ( R ct ) and double-layer capacitance ( C dl ) at the particle interface. − The tail in the impedance spectra corresponds to the capacitive Li + intercalation into the particles. No feature relating to the charge transfer through the SEI layer was observed.…”