Memory Effect in Lithium Titanate Driven by Interfacial Oxygen Vacancies

Abstract

Memory effect is undesirable abnormal voltage behavior in batteries that appears as a result of certain usage history. Al-doped Li 4 Ti 5 O 12 (LTO), LiFePO 4 , and TiO 2 that undergo phase transformations during lithiation/delithiation are known to possess a memory effect. Memory effect in these materials typically arises because of delayed onset of potential overshoot at the beginning of the delithiation voltage profile. In general, memory effect is associated with the sluggish electrochemical kinetics of phase transformation. Herein, we reveal a new source of memory effect in undoped LTO, which originates from an unstable LTO/electrolyte interface that can be produced by a distorted and defect-ridden particle surface. Electrochemical impedance spectroscopy shows that deep lithiation leads to variable resistance toward charge transfer, which produces a memory effect in the proceeding cycles. This work indicates the importance of controlling the particle/electrolyte interface to prevent an unprecedented memory effect in LTO.

Amorphization-Driven Lithium Ion Storage Mechanism Change for Anomalous Capacity Enhancement

“…EIS analysis was employed to further investigate the interfacial charge transfer processes. The Nyquist spectra of the TNO samples (Figure A–C) showed three semicircles and a low-frequency capacitive tail, which is a common observation in Li-ion storage materials. − The first semicircle in the high-frequency region is attributed to the charge-transfer resistance through the SEI layer ( R SEI ). The second semicircle originates from the interfacial charge-transfer resistance at the electrolyte/particle interface ( R ct ).…”

Overview of the oxygen vacancy effect in bimetallic spinel and perovskite oxide electrode materials for high-performance supercapacitors

“…88 The defects or vacancies of metal atoms depend on their paramagnetic transition intensities, which can be represented with a constant parameter ‘ g. ’ The paramagnetic transition at g = 2.003 manifests the presence of OVs in the materials in EPR measurement. 89–91 For example, Wang et al reported mesoporous NiCo 2 O 4 and Co 3 O 4 microspheres by a facile synthesis strategy and subjected them to a partial reduction. The intrinsic behavior and corresponding surface area of the microspheres in the above spinel materials were enhanced as the reduction progressed.…”

Recent progress in Co‐free, Ni‐rich cathode materials for lithium‐ion batteries

“…[1][2][3][4] Lithium-ion batteries (LIBs) are in enormous demand in many applications such as vehicle transportation, stationary energy storage, portable electronics, and large-scale energy systems. [5][6][7][8][9][10][11][12][13][14][15] The attractive applications of LIBs are mainly due to their superior energy density and longer service life, [16][17][18][19][20][21] and these properties are dependent on the electrochemical performance of the cathode electrode material. [22][23][24] The cathode electrode design must account for material cost, safety, and structural stability capabilities, and it can be used to create promising high-performance LIBs.…”