In situ probing behaviors of single LiNiO₂ nanoparticles by merging CAFM and AM–FM techniques

Abstract

Probing single active nanoparticles of Li-ion battery electrodes is challenging but important to reveal their behaviors including morphology, mechanical properties and electrochemical reactions with an electrolyte. In this work, we in situ investigated voltage-induced behaviors of single LiNiO nanoparticles by merging conductive atomic force microscopy (CAFM) and amplitude modulation-frequency modulation (AM-FM) techniques. The former was used to apply a voltage between a selected single nanoparticle and a substrate through its tip, while the latter was done for imaging. Evolution in the morphology and stiffness of the nanoparticles induced by different voltages under air and dried argon atmospheres was tracked, respectively. The evolution mechanisms related to electrochemical reactions were discussed in detail. These results suggest that the merged techniques would provide an indirect and effective approach to study the behaviors and electrochemical reactions of electrode materials on the nanometer scale and even single nanoparticles.

Bimodal AFM-Based Nanocharacterization of Cycling-Induced Topographic and Mechanical Evolutions of LiMn2O4 Cathode Films

“…Yang et al used this technique to characterize the surface structure and mechanical properties of the lithium-rich cathode thin films at different stages of charge/discharge and the lithium-rich nanoparticles at different voltages . Our group previously used the bimodal AFM to investigate cycle-induced evolutions in surface topography and contact stiffness of the LiCoO 2 films and combined the bimodal AFM with conductive AFM (c-AFM) to in situ probe the voltage-induced morphology and nanomechanical behaviors of the LiNiO 2 nanomaterials …”

“…27 Our group previously used the bimodal AFM to investigate cycle-induced evolutions in surface topography and contact stiffness of the LiCoO 2 films 28 and combined the bimodal AFM with conductive AFM (c-AFM) to in situ probe the voltage-induced morphology and nanomechanical behaviors of the LiNiO 2 nanomaterials. 29 In this study, we further expanded the bimodal AFM to investigate the charge/discharge cycling-induced evolutions in surface topography and elastic modulus of pure LiMn 2 O 4 films at the nanoscale. Considering the results obtained by the bimodal AFM and other characterization techniques, including galvanostatic charging/discharging, nanoindentation, c-AFM, and current−voltage (I−V) measurement method, the mechanisms of degradation of elastic modulus are explored.…”

Visualization and Quantification of State of Charge-Dependent Young’s Modulus of LiMn2O4 Nanosized Particles by Bimodal AFM

“…Scanning probe microscopy (SPM) has demonstrated its great capability to probe the surface topography, conductivity, and surface potential of the battery electrode materials with nanometer resolution. 1−3 Especially as an emerging technique in SPM, bimodal atomic force microscopy (bimodal AFM) has been successfully applied to measure both the surface topography and the nanomechanical properties of the materials simultaneously, involving lithium-rich cathode, 4,5 LiCoO 2 , 6,7 and LiNiO 2 8 cathode materials. This capability of the bimodal AFM is of high importance because the mechanical properties are crucial for preventing the mechanical failure of the electrode materials during (de)lithiation in advanced lithiumion batteries.…”

Insight into the intrinsic mechanism of improving electrochemical performance via constructing the preferred crystal orientation in lithium cobalt dioxide

“…Direct visualization of the electronic conductivity evolutions on different crystal faces enable better understanding the origin of polarization-dependent battery performance. Recently, new techniques have been developed to allow the Atomic Force Microscopy (AFM) to be operated in liquid conditions [14][15][16][17], which can image the cathode materials at charging and discharging processes [18,19], thus providing the capability to directly probe the physical-chemical properties of the liquid/solid interface. Here we employed the in situ current-sensing Atomic Force Microscopy (CSAFM) to study the interfacial conductivity on the surface of LCO crystal grains and to probe the IMT on a certain crystal face.…”