Lithium–antimony–lead liquid metal battery for grid-level energy storage

Abstract

The ability to store energy on the electric grid would greatly improve its efficiency and reliability while enabling the integration of intermittent renewable energy technologies (such as wind and solar) into baseload supply. Batteries have long been considered strong candidate solutions owing to their small spatial footprint, mechanical simplicity and flexibility in siting. However, the barrier to widespread adoption of batteries is their high cost. Here we describe a lithium-antimony-lead liquid metal battery that potentially meets the performance specifications for stationary energy storage applications. This Li||Sb-Pb battery comprises a liquid lithium negative electrode, a molten salt electrolyte, and a liquid antimony-lead alloy positive electrode, which self-segregate by density into three distinct layers owing to the immiscibility of the contiguous salt and metal phases. The all-liquid construction confers the advantages of higher current density, longer cycle life and simpler manufacturing of large-scale storage systems (because no membranes or separators are involved) relative to those of conventional batteries. At charge-discharge current densities of 275 milliamperes per square centimetre, the cells cycled at 450 degrees Celsius with 98 per cent Coulombic efficiency and 73 per cent round-trip energy efficiency. To provide evidence of their high power capability, the cells were discharged and charged at current densities as high as 1,000 milliamperes per square centimetre. Measured capacity loss after operation for 1,800 hours (more than 450 charge-discharge cycles at 100 per cent depth of discharge) projects retention of over 85 per cent of initial capacity after ten years of daily cycling. Our results demonstrate that alloying a high-melting-point, high-voltage metal (antimony) with a low-melting-point, low-cost metal (lead) advantageously decreases the operating temperature while maintaining a high cell voltage. Apart from the fact that this finding puts us on a desirable cost trajectory, this approach may well be more broadly applicable to other battery chemistries.

Low-Temperature Molten Salt Electrolytes for Membrane-Free Sodium Metal Batteries

“…anode: A liq → A z+ + ze − [1] cathode: A z+ + ze − → A(in B) liq [2] overall: A liq → A(in B) liq [3] E cell,eq = − Ḡ cell z F = − RT z F lna A(in B)liq [4] Because all three active battery components are liquid phase, the system is able to operate at high current densities with minimal overpotential losses. In addition, because the cell is restored to its virgin liquid state upon each recharge, the device is immune to solid-state failure mechanisms common in lithium-ion batteries 3 and, as a result, is expected to provide exceptionally long amortizable service lifetimes.…”

“…As a result, there is great interest in lowering the operating temperature of the device through careful selection of the three active components. Because there are a variety of earth-abundant and low-temperature anode 2,4 and cathode metals 1 and alloys the component that most frequently sets the operating temperature of the device is the molten salt electrolyte. Such dependencies motivate the search for newer and lower-melting electrolytes to unlock both lower temperature battery designs as well as cheaper device operating costs on a $/kWh-cycle basis.…”

Sulphur-impregnated flow cathode to enable high-energy-density lithium flow batteries

“…E nergy storage system is a critical enabling factor for deploying unstable and intermittent renewable power sources, such as solar and wind power sources [1][2][3][4][5][6] . Redox flow batteries (RFBs) are promising technologies for large-scale electricity storage, owing to its design flexibility in decoupling power and energy capacity [7][8][9][10] .…”

Electrochemical Determination of the Thermodynamic Properties of Lithium-Antimony Alloys

“…1,2 Prior investigations of this system are limited and are generally focused on intermetallic characterization. [3][4][5] Notably, two groups have studied the intermetallics Li 2 Sb(s) and Li 3 Sb(s) electrochemically, determining the thermodynamic electric potential and Gibbs free energy of formation of the compounds between 355 o C and 600 o C. 3,6,7 As for liquid alloys, Nikitin et al 3 studied the deposition of lithium by cathodic polarization of liquid antimony and observed that electrode potential varied inversely with both current density and degree of lithiation, which they attributed to formation of composition gradients.…”