Direct measurements of size-independent lithium diffusion and reaction times in individual polycrystalline battery particles

Abstract

Polycrystalline Li(Ni,Mn,Co)O2 (NMC) secondary particles are the most common cathode materials for Li-ion batteries. During electrochemical (dis)charge, lithium is believed to diffuse through the bulk and enter (leave) the secondary...

Impact of Mechanical Degradation in Polycrystalline NMC Particle on the Electrochemical Performance of Lithium-Ion Batteries

“…A similar phenomenon of reduced overpotential or chargetransfer resistance between the NMC particle and electrolyte was observed due to particle cracking in the experimental study. 49,50,79 Janek and colleagues 49,50 proposed that the cracked NMC particle would have better performance than the pristine, uncracked ones for the initial cycles, affirming the positive impact of cracking on the overall performance of lithium-ion batteries. This advantage is linked to the penetration of liquid electrolyte into the cracks of secondary particles, leading to a significant increase in the electrochemically active surface area and shorter diffusion paths inside the active particles, thereby enhancing the kinetic performance of secondary particles.…”

“…In reality, the diffusion and reaction times could essentially be independent of the particle size. 48 Cracks and fractures in the particles create new pathways for lithium ions to diffuse, leading to changes in the lithium concentration field and influencing the electrochemical performance of the battery. 49 In contrast to solid electrolytes, liquid electrolytes can infiltrate cracks, enhancing ion access to the particles.…”

Bismuth-doping boosting Na+ diffusion kinetics of layered oxide cathode with radially oriented {010} active lattice facet for sodium-ion batteries

“…16−18 Furthermore, rationally designing secondary microparticles assembled with primary nanoparticles is effective at improving diffusion kinetics by shorting the ion diffusion pathway. 19,20 However, the diffusion of Na + into the electrolyte is difficult as it entails crossing through multiple grain boundaries due to the random agglomeration of primary particles. 21 In addition, the nanoparticles with large specific surface areas in secondary microparticles easily initiate surface parasitic reactions with electrolyte, accelerate the degradation of the cathode material, and thus result in capacity decay after long cycling.…”

“…To alleviate the problems, exposing sufficient {010} facets of primary particles is one effective way to provide additional ion transport channels for enhancing Na + diffusion kinetics. , A surfactant-assisted synthesis method was used to effectively promote inducing the growth of the exposed {010} active planes, by lowering the high surface energy of the {010} facets with the addition of surfactants of sodium dodecyl sulfate and polyvinylpyrrolidone. , A surfactant-free coprecipitation method was able to construct a porous and hollow architecture with exposed {010} facets. − Furthermore, rationally designing secondary microparticles assembled with primary nanoparticles is effective at improving diffusion kinetics by shorting the ion diffusion pathway. , However, the diffusion of Na + into the electrolyte is difficult as it entails crossing through multiple grain boundaries due to the random agglomeration of primary particles . In addition, the nanoparticles with large specific surface areas in secondary microparticles easily initiate surface parasitic reactions with electrolyte, accelerate the degradation of the cathode material, and thus result in capacity decay after long cycling. − Therefore, simultaneous combination of the oriented crystal facets and the nanoplatelet-containing microspheres could greatly enhance both the structural stability and Na + diffusion kinetics.…”

Materials Horizons Emerging Investigator Series: Professor Yiyang Li, University of Michigan, USA

“…Last year, we published a paper in the RSC's Energy and Environmental Science , where we used microfabrication to charge and discharge individual battery particles. 6 Our process is not too different from creating a device using a nanowire or an exfoliated flake of a 2D material, but has almost never been done in the field of energy storage. It is worth remembering that Profs John Goodenough, 7 Stanley Whittingham, 8 and Akira Yoshino 9 all researched electronic materials before they worked on the Li-ion battery that won them the Nobel Prize in 2019.…”