RISE

Research Interests

 

Understanding and addressing electrochemo-mechanical challenges in solid-state batteries (SSBs) is the key focus of our investigation. Currently we are focused on evaluating the role of anisotropic diffusion induced stress as a function of defect topology and density (i.e., 1D/2D  defect) in cathode composites, and influence of microstructure (of solid-electrolyte, and lithium metal anode) on cell performance e.g., impedance, fast charging etc. Also we focus on designing systems that can lead to interfacial stress (~GPa) mitigation for enabling anode-free SSBs. We develop and employ techniques like operando impedance spectroscopy, in-situ electrochemical-SEM/XPS/Raman/AFM measurements to investigate the buried interfaces.

Email: dheeraj.kumar.singh@tcgcrest.org

 

Origin of the lithium metal anode instability in solid-state batteries during discharge

Non-Linear Kinetics of The Lithium Metal Anode on Li₆PS₅Cl at High Current Density: Dendrite Growth and the Role of Lithium Microstructure on Creep

Abstract

 

 

 

Chronopotentiometric profiles (left figure) for lithium deposition on a a) flawed grain surface and b) flaw-free grain surface region. Insets in (a) and (b) show magnified data of the initial overpotentials. c) SEM image showing the tungsten needle contacted at a flawed surface region prior to lithium deposition whereas d) shows the lithium deposition at t = 39 s. e,f) SEM images of the temporal evolution of the lithium insertion driven LPSCl fracture. Arrows indicate the crack extension. g) SEM image of a flaw-free grain surface in contact with the tungsten needle prior to the deposition. h,i) SEM images showing preferential vertical growth of lithium with time. j) SEM image of (g) after galvanostatic cycle. k) Schematic indicating lithium insertion driven fracture. l) Vertical growth of lithium occurs on a flaw free grain surface region. The dotted lines in (k) and (l) indicate the contact area. The curved arrow indicates free growth of lithium above the surface of LPSCl.

 

 

 

In the right figure the CVs of lithium microelectrodes. a) Symmetric, and b) asymmetric CV of the Li microelectrode at 0.2 mV s⁻¹. The numbered arrows indicate the scan direction. c) Schematic of interfacial contact evolution during stripping and plating. Interfacial contact at high and low overpotential is expanded in (d). There are only a few contacts at high overpotentials compared to low overpotentials resulting in increased contact stresses. e) Creep deformation of a representative grain in the vicinity of the void (indicated by the dashed circle in (d)) subjected to time-dependent or the anodic overpotential dependent inhomogeneous stress. Grain boundary diffusion indicated by solid circles or equivalently vacancy transport (indicated by square box) in the opposite direction drives creep, leading to interfacial contact healing. A net imbalance of stresses upon stripping drives deformation via dislocation climb creep (DCC) or glide assisted flow. The contour of grain boundary prior to deformation (depicted by the dashed red line) is overlayed on the deformed grain. σ_c, compressive stress and σ_t, tensile stress.

Education

• Post-doctoral fellow, Justus-Liebig University, Germany under Prof. Jürgen Janek (2019-2022).

• Post-doctoral fellow, JNCASR, Bangalore under Prof. M. Eswaramoorthy (2018-2019)

• Ph.D. (Materials Science), JNCASR, Bangalore under Prof. M. Eswaramoorthy (2012-2018)

• M.Sc. (Chemistry), Sri Sathya Sai Institute of Higher Learning, Puttaparthi (2010-2012).

• B.Sc. (Hons.) in Chemistry, Sri Sathya Sai Institute of Higher Learning, Puttaparthi (2007-2010).

 

More details of his publications can be found here:

https://scholar.google.co.in/citations?hl=en&user=Q_M_BQQAAAAJ&view_op=list_works&sortby=pubdate

 

Publications