Nontraditional, Safe, High Voltage Rechargeable Cells of Long Cycle Life

Abstract

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.

Magnetic Field–Suppressed Lithium Dendrite Growth for Stable Lithium‐Metal Batteries

“…[5] It not only penetrates the separator to induce the short circuit of the batteries, [6] but also generates high surface area in the anode to accelerate the unwanted side reactions between electrolytes and lithium metal, resulting in the electrolyte depletion and the subsequent battery failure. [13] For creating artificial SEI layer on the anode, gas treatment [14] (N 2 , O 2 , CO 2 , or SO 2 ), liquid treatment (Li 3 PO 4 [15] and Cu 3 N/styrene−butadiene rubber [16] ), and physical deposition of nanofilm (Al 2 O 3 , [17] carbon, [18] and organic polymer [19] ) are the three typical methods by accessing the internal interface of the battery. Those strategies include electrolyte optimization, artificial solid electrolyte interphase (SEI) design, and synthesis of 3D current collector.…”

Thermodynamic considerations of same-metal electrodes in an asymmetric cell

“…For the SS + Li/Li + -glass/S + C + Al + SS cell, a positive electrode slurry containing 60 wt% of S 8 (1.08 mg), 30 wt% (0.54 mg) of carbon black Super P and 10 wt% PVDF (0.18 mg) was prepared as in (Braga et al 2018). The slurry was then doctor bladed onto an aluminum foil current collector.…”

“…The slurry was then doctor bladed onto an aluminum foil current collector. The Li-glass electrolyte in a non-woven recyclable paper matrix was prepared as in (Braga et al 2017;Braga et al 2018). The cell was assembled in a CR2032 casing.…”

“…2, 3 and 4. It is also highlighted that the band gaps are usually underestimated in DFT calculations (Brothers et al 2008) by a factor of ca. 1.6.…”

Diffusive dynamics in an amorphous superionic conductor

“…Amongst the glassy superionic conductors, it is commonly an alkali species that acts as the mobile cationic charge carrier. For instance, glassy lithium oxochloride is of utmost current technological importance as the electrolyte of a proposed solid state battery [7]. More interesting from a fundamental point of view is the situation where the mobile alkali ions act as modifiers of a distinct glass backbone structure exemplified by alkali borate glasses: Here the end member borate oxide is a prototypical glass former in its own right, while the composition series (A 2 O) x (B 2 O 3 ) 100−x , with A an alkali metal, displays a pronounced vitrification tendency up to x ≈ 50.…”