Critical stripping current leads to dendrite formation on plating in lithium anode solid electrolyte cells

Abstract

A critical current density on stripping (CCS) is identified that results in dendrite formation on plating and cell failure. When the stripping current density removes lithium from the interface faster than it can be replenished, voids form in the lithium at the interface and accumulate on cycling increasing the local current density at the interface and ultimately leading to dendrite formation on plating, short-circuit and cell death. This occurs even when the overall current density is significantly below the threshold for dendrite formation on plating. For the Li / Li6PS5Cl / Li cell, this is 0.2 and 1 mA•cm -2 at 3 and 7 MPa pressure respectively, compared with a critical current for plating of 2 mA•cm -2 at both 3 and 7 MPa. The pressure dependence on stripping indicates creep rather than Li diffusion is the dominant mechanism transporting Li to the interface. The critical stripping current is a major factor limiting the power density of lithium anode solid state cells. Significant pressure may be required to achieve even modest power densities in solid state cells.

Correlating Macro and Atomic Structure with Elastic Properties and Ionic Transport of Glassy Li2S‐P2S5 (LPS) Solid Electrolyte for Solid‐State Li Metal Batteries

“…Even though the CCD increased by a factor of almost three, the voltage traces of the hot‐pressed sample showed significant overpolarization suggesting unstable cycling at the higher current densities (Figure S9c, Supporting Information). The tests performed at different stack pressures elucidated that the overpolarization was a result of loss in contact area due to void formation between the electrode and electrolyte as it has been observed and reported in other systems, such as: Li‐argyrodite (Li 6 PS 5 Cl), [ 41 ] Li‐LLZO, [ 42,43 ] and Na‐Na ß'' alumina. [ 44 ] Given that Li creep is the dominant mechanism transporting Li to the interface rather than Li diffusion, [ 41,42 ] such replenishment can be aided via stack pressure or temperature.…”

Solid‐State Lithium–Sulfur Battery Enabled by Thio‐LiSICON/Polymer Composite Electrolyte and Sulfurized Polyacrylonitrile Cathode

“…Grain boundaries, which inevitably exist in the particle stacking of solid electrolytes, compromise the ability of solid electrolytes in preventing HSAL growth 20. At the interface of the solid electrolyte with Li metal anode, insufficient wetting and rigid contact result in void formation during cycling, which further promotes irregular Li deposition, leading to high local stress and eventually Li metal degradation 21,22…”

“…[20] At the interface of the solid electrolyte with Li metal anode, insufficient wetting and rigid contact result in void formation during cycling, which further promotes irregular Li deposition, leading to high local stress and eventually Li metal degradation. [21,22] Besides the drawbacks of compressed inorganic solid electrolyte pellets in SSLSBs, the intrinsic limitations of the sulfur cathode are even more prominent in SSLSBs. [23] The poor electronic conductivity of sulfur as well as its discharge product (Li 2 S) results in low reversibility and low active material utilization.…”

Sodium Plating from Na‐β″‐Alumina Ceramics at Room Temperature, Paving the Way for Fast‐Charging All‐Solid‐State Batteries

“…Owing to its high ionic conductivity, low electronic conductivity, and stability against sodium metal, Na‐β″‐alumina is already commercially employed in high‐temperature sodium–nickel‐chloride (NaNiCl) and sodium–sulfur (NaS) batteries operating near 300 °C . However, high interfacial resistance, possibly associated with poor sodium wetting and the presence of surface impurities, has impeded its use as solid electrolyte for room‐temperature batteries …”