arXiv subjects

Changdeuck Bae

Publications and source records attributed to Changdeuck Bae.

3 recordsLinked to original sources

arXiv2026

Parabolic-growth universality and its nucleation-driven breakdown across lithium-battery anode chemistries

Solid-electrolyte interphase (SEI) growth is widely modeled cell-by-cell with chemistry-specific closures, yet its underlying kinetic scaling is rarely tested across chemistries. By compiling cycle-resolved data from public long-cycle datasets covering four anode configurations -- graphite, silicon composite, lithium metal, and anode-free -- we show that the cumulative interphase-loss index Lambda_int obeys the parabolic law Lambda_int = A_chem * sqrt(1 - Theta_Li) in three of the four chemistries, with an exponent indistinguishable from alpha = 1/2 within experimental uncertainty. The chemistry-specific prefactor A_chem spans an order of magnitude, but the diffusion-limited parabolic kinetics is preserved. The fourth chemistry, anode-free configurations, deviates with a super-parabolic exponent alpha approx 0.77, consistent with a nucleation-controlled growth regime. We rationalize the result using the Tammann-Deal-Grove parabolic-growth framework adapted to interphase formation and identify the conditions under which universality is recovered. The observed regularity reduces SEI modeling complexity to a single rate constant per chemistry and provides a sharp falsifiable test for next-generation cell formats.

cond-mat.mtrl-sci↗

arXiv2026

Saddle-node bifurcation in interfacial morphology selects battery degradation phase

We propose a minimal nonlinear closure ODE for the dynamic active-area factor of a battery interface and show that it exhibits a saddle-node bifurcation when the smoothing rate saturates with surface roughness. The closure is the simplest physically motivated extension of a recently introduced single-fixed-point closure [C. Bae, in preparation (2026)]: u = K - u/(1 + alphau^2), where u = xi - 1 is the dimensionless excess active area, K the dimensionless drive, and alpha a single saturation parameter. The bifurcation occurs at K_c = 1/(2sqrt(alpha)), separating a smooth passivating phase from a morphologically unstable phase. Mapping four canonical anode configurations -- graphite, silicon composite, lithium metal, and anode-free Li/Cu -- onto the closure via end-of-cycling steady-state xi extracted from publicly available long-cycle data populates the stable branch with monotonically increasing K/K_c ratios: graphite (~0.01), silicon composite (~0.24), lithium metal (~0.73), and anode-free (~0.95). The anode-free configuration sits within 5% of the saddle-node threshold, predicting a vanishingly small operational stability window in current density, temperature, and electrolyte composition. We test three falsifiable predictions of the framework -- a critical current density, a critical temperature shift, and a mean-field critical-slowing-down exponent -- and find them broadly consistent with publicly available data. We argue that this near-critical position is universal to nucleation-controlled deposition on non-passivating substrates.

cond-mat.mtrl-sci↗

arXiv2026

Interfacial breathing as a dynamic failure law in all-solid-state batteries: amplitude, phase lag and dual-timescale memory as design principles

All-solid-state batteries fail not only by bulk transport limits, but by a reactive interface that evolves during cycling. We show that degradation is governed by two coupled processes: interfacial breathing, the cycle-scale oscillation of lithium contact, and reactive memory, the slow accumulation of electrolyte decomposition. Four descriptors capture breathing, together with a memory metric based on decomposed interphase thickness. A reduced electrochemical benchmark shows that ionic conductivity has little effect on mean discharge voltage, whereas cathode electrolyte interphase resistance causes major voltage and energy losses. A phase-field model of a sulfide-based cell shows that higher stack pressure strongly suppresses breathing-related fluctuations, but leaves reactive memory nearly unchanged. Thus, pressure controls breathing, not memory. The resulting regime map identifies void-growth-dominant, healing-dominant, and interphase-memory-dominant regions. The theory also predicts energy-density rank inversion with C rate, where an initially superior architecture loses advantage at higher rate as breathing intensifies and interphase memory locks in. The design target is therefore not merely higher conductivity or lower resistance, but simultaneous suppression of breathing and independent control of reactive memory through interphase chemistry.

cond-mat.mtrl-sci↗