High Specific Energy Density Aqueous Lithium-Metal Chloride Rechargeable Batteries

Abstract

Here we show the feasibility of a novel high energy density battery with a Li anode and a MCl 2 (M = Fe, Co, Ni, Cu, and Zn) aqueous cathode separated by a water-stable NASICON-type lithium-ion conducting solid electrolyte of Li 1.4 Al 0.4 Ge 0.2 Ti 1.4 (PO 4 ) 3 (LAGTP). The Li/MCl 2 (M = Co, Ni, and Zn) aqueous solution with LiCl cells were successfully charged and discharged. In contrast, the Li/MCl 2 (M = Fe and Cu) cells were discharged, but they could not be charged, because FeCl 2 and CuCl 2 reacted with lithium-ions to produce an insoluble compound. The Li/CoCl 2 and Li/NiCl 2 cells showed discharge cathode capacities of 326 and 412 mAh g −1 at 60 • C and 4.0 m A cm −2 , respectively, which correspond to 78 and 100% to the theoretical capacity, respectively. The estimated specific energy densities calculated using the mass of cell components with a 0.1 mm thick LAGTP separator (except the packaging) were 617 and 670 Wh kg −1 for the Li/CoCl 2 and Li/NiCl 2 cells, respectively, which are approximately two times higher than those for conventional lithium-ion batteries. Electrical vehicles (EVs) are considered to reduce CO 2 emissions and the consumption of fossil fuels because the total energy conversation efficiency of batteries is higher than that of internal combustion (IC) engines.1 However, the driving range of commercialized EVs with the current lithium-ion batteries is considerably lower than that of vehicles with IC engines because the specific energy density for the lithium-ion battery is too low compared with the IC engine.2 The calculated specific energy density of a gasoline engine for automotive applications is estimated to be around 1700 Wh kg −1 , determined using the reaction heat of gasoline and a tank to wheel efficiency of 12.6%.2 The theoretical specific mass and volume energy densities calculated for a lithium-ion battery based on a carbon anode and a LiCoO 2 based cathode are 387 Wh kg −1 and 1015 Wh dm −3 , respectively, 3,4 the former of which is around one fourth of that for the IC engine. Many types of battery systems beyond lithium-ion batteries have been proposed, such as lithium-sulfur and lithium-air rechargeable batteries.3,5-9 The lithium-sulfur battery is a very attractive battery system because of its high theoretical energy density (ca. 2600 Wh kg −1 and 2199 Wh dm −3 ). 3,5 However, even after several decades' research and development, the lithium-sulfur battery has still not reached mass commercialization. Several problems inherent in the cell chemistry remain, such as poor electrode rechargeability and limited rate capability due to the insulative nature of sulfur and the solid reaction products, and fast capacity fade due to the generation of various soluble polysulfide intermediates. The calculated energy densities for the non-aqueous lithium-air cell are as high as 3505 Wh kg −1 and 3436 Wh dm −3 . 3 The specific mass energy density is quite attractive for the power source in EVs and interest has expanded rapidly in recent years. Although significant progress has be...

High Energy Density Rechargeable Aqueous Lithium Batteries with an Aqueous Hydroquinone Sulfonic Acid and Benzoquinone Sulfonic Acid Redox Couple Cathode

“…The calculated specific energy density of the cell generally depends on the specific area capacity [34], and the cell performance of a solid active material such as LiCoO2 in the lithium-ion batteries depends on the thickness of the electrode [35]. However, the cell performance of a cell with a liquid catholyte shows no significant dependence on the specific area capacity, as reported in the literature [11]. Hence, the proposed Li/BQS battery with a liquid catholyte could provide high energy density at a high area capacity.…”

“…The specific energy density of the Li/LiMn2O4 cell based on the mass of the electrodes was estimated to be 446 Whkg -1 . Imanishi and co-workers [11][12][13] proposed a higher specific energy density aqueous lithium battery that consisted of a lithium anode with a liquid electrolyte, an aqueous MCl2 (M = Co, Ni, and Sn) solution catholyte, and a Li1.4Al0.4Ge0.2Ti1.4(PO4)3 (LAGTP) separator. The theoretical specific energy density of the Li/NiCl2 cell was as high as 1047 Whkg -1 based on the weights of lithium and NiCl2 and was at least twice of the conventional lithium-ion battery.…”

Aqueous Lithium--Air Batteries with High Power Density at Room Temperature under Air Atmosphere

“…However, a major disadvantage of lead-acid batteries is their low energy density. In addition to aqueous lithium-air batteries, several other advanced aqueous rechargeable batteries have been proposed in the last few decades, including the aqueous lithium-metal chloride [32], aqueous lithium-Fe(CN) 6 3-/Fe(CN) 6 -4- [33], and aqueous Sn/LiCoPO 4 [34] batteries [10]. Among these, aqueous lithium-air battery, the one used in the present study as well, is reported with a high energy density of over 500 Wh kg -1 [27] and a low round-trip overpotential at a high current density of 2.0 mA cm -2 , in air and at room temperature.…”

Water-Stable High Lithium-Ion Conducting Solid Electrolyte of Li1.4Al0.4Ge0.2Ti1.4(PO4)3–LiCl for Aqueous Lithium-Air Batteries

“…3− /Fe(CN) 6 4− redox couple, and Imanishi and colleagues (Morita et al, 2017(Morita et al, , 2018Watanabe et al, 2019) proposed an aqueous lithium battery with a lithium anode and an aqueous MCl 2 /M (M = Sn, Co, and Ni) redox couple. Wu and colleagues reported a lithium battery using an aqueous electrolyte solution with a lithium anode and a LiFePO 4 (Hou et al, 2013;Chang et al, 2016), LiCoO 2 (Wang et al, 2013b), or LiMn 2 O 4 (Wang et al, 2013a) cathode.…”