The advent of a Li+ or Na+ glass electrolyte with a cation conductivity σi > 10−2 S cm−1 at 25 °C and a motional enthalpy ΔHm = 0.06 eV that is wet by a metallic lithium or sodium anode is used to develop a new strategy for an all-solid-state, rechargeable, metal-plating battery.

Precursors of the crystalline antiperovskites A3−xHxOCl (A = Li or Na and 0 < x < 1) can be rendered glass/amorphous solid Li+ or Na+ electrolytes by the addition of water to its solvation limit with/without the addition of a small amount of an oxide or hydroxide.

A room-temperature all-solid-state rechargeable battery cell containing a tandem electrolyte consisting of a Li-glass electrolyte in contact with a lithium anode and a plasticizer in contact with a conventional, low cost oxide host cathode was charged to 5 V versus lithium with a charge/discharge cycle life of over 23,000 cycles at a rate of 153 mA·g of active material. A larger positive electrode cell with 329 cycles had a capacity of 585 mAh·g at a cutoff of 2.5 V and a current of 23 mA·g of the active material; the capacity rose with cycle number over the 329 cycles tested during 13 consecutive months. Another cell had a discharge voltage from 4.5 to 3.7 V over 316 cycles at a rate of 46 mA·g of active material. Both the Li-glass electrolyte and the plasticizer contain electric dipoles that respond to the internal electric fields generated during charge by a redistribution of mobile cations in the glass and by extraction of Li from the active cathode host particles. The electric dipoles remain oriented during discharge to retain an internal electric field after a discharge. The plasticizer accommodates to the volume changes in the active cathode particles during charge/discharge cycling and retains during charge the Li extracted from the cathode particles at the plasticizer/cathode-particle interface; return of these Li to the active cathode particles during discharge only involves a displacement back across the plasticizer/cathode interface and transport within the cathode particle. A slow motion at room temperature of the electric dipoles in the Li-glass electrolyte increases with time the electric field across the EDLC of the anode/Li-glass interface to where Li from the glass electrolyte is plated on the anode without being replenished from the cathode, which charges the Li-glass electrolyte negative and consequently the glass side of the Li-glass/plasticizer EDLC. Stripping back the Li to the Li-glass during discharge is enhanced by the negative charge in the Li-glass. Since the Li-glass is not reduced on contact with metallic lithium, no passivating interface layer contributes to a capacity fade; instead, the discharge capacity increases with cycle number as a result of dipole polarization in the Li-glass electrolyte leading to a capacity increase of the Li-glass/plasticizer EDLC. The storage of electric power by both faradaic electrochemical extraction/insertion of Li in the cathode and electrostatic stored energy in the EDLCs provides a safe and fast charge and discharge with a long cycle life and a greater capacity than can be provided by the cathode host extraction/insertion reaction. The cell can be charged to a high voltage versus a lithium anode because of the added charge of the EDLCs.

The ability for electrochemical cells to self-charge for extended periods of time is desirable for energy storage applications. While self-oscillation is a phenomenon found in human-made dynamic systems and in nature, its appearance in electrochemical cells has not been reported or anticipated. Here, we chose an electrochemical cell containing two electrodes separated by a self-organizing glass electrolyte containing alkali cations. The ferroelectric character of the electrolyte, with an impressively high dielectric constant of 106–107, supported self-charge and self-oscillation. After fabrication, the cells were characterized to determine the electrical impedance, dielectric spectroscopy, and electrochemical discharge. The electrochemical cells also displayed negative resistance and negative capacitance. Negative capacitance is due to the formation of an inverted capacitor between the double-layer capacitor formed at the negative electrode/electrolyte interface and the dipoles of the ferroelectric-electrolyte. Negative resistance is triggered by the formation of an interface phase, which leads to a step-change of the chemical potential of the electrode. The electrochemical cell demonstrates an entanglement between negative resistance, negative capacitance, self-charge, self-cycling, and the activation energy vs thermal energy or external work. The phenomenon of self-cycling is enhanced at low temperatures where the activation energy is higher than the thermal energy. This demonstration extends the Landau-Khalatnikov model for a ferroelectric to a bistable device in which the bistability resides in an electrode. The results reported here reveal the first report of negative capacitance and negative resistance existing in the same process, which can lead to valuable advancements in energy storage devices and in low-frequency applications.