Solid-state battery based on an ion-conductive matrix composed of camphor or 2-adamantanone

Abstract

The present invention relates to a solid-state battery, particularly a lithium-ion solid-state battery, composed of one or more battery cells, which have an ion-conducting solid matrix (2) as solid electrolyte, which matrix is embedded between two electrodes (1, 3). The proposed solid-state battery is characterized in that the solid matrix (2) is formed form camphor, 2-adamantanone or a mixture of one of the two with one or more other substances. Owing to the use of camphor or 2-adamantanone, the solid electrolyte is mechanically stable and has good ionic conductivity in a wide temperature range.

Claims

1. A solid-state battery composed of one or more battery cells, which comprise an ion-conducting solid matrix for forming a solid electrolyte, which matrix is arranged between two electrodes, characterized in that the solid matrix is a plastic crystal formed from camphor or 2-adamantanone or from a mixture of camphor or 2-adamantanone with one or more other substances, which do not form an alloy with camphor or 2-adamantanone or with a mixture of camphor and 2-adamantanone.

2. The solid-state battery according to claim 1, characterized in that at least one of the electrodes is a composite electrode made from an active material, camphor and a current collector as well as other optional constituents.

3. The solid-state battery according to claim 1, characterized in that both electrodes are composite electrodes that contain camphor.

4. The solid-state battery according to claim 2, characterized in that camphor is contained in the composite electrode or composite electrodes in a proportion between 10 and 20% by volume.

5. The solid-state battery according to claim 1, characterized in that at least one of the electrodes is a composite electrode made from an active material, 2-adamantanone and a current collector as well as other optional constituents.

6. The solid-state battery according to claim 1, characterized in that both electrodes are composite electrodes which contain 2-adamantanone.

7. The solid-state battery according to claim 5, characterized in that 2-adamantanone is contained in the composite electrode or composite electrodes in a proportion between 10% and 20% by volume.

8. The solid-state battery according to claim 2, characterized in that the composite electrode or composite electrodes include(s) additives for improving electrical conductivity.

9. A method for forming a solid electrolyte of a solid-state battery, the method comprising: providing camphor or 2-adamantanone; and forming a solid matrix of plastic crystal from said camphor or 2-adamantanone, or from a mixture of said camphor or 2-adamantanone with one or more other substances, which do not form an alloy with camphor or 2-adamantanone or with a mixture of camphor and 2-adamantanone.

10. The solid-state battery according to claim 5, characterized in that the composite electrode or composite electrodes include(s) additives for improving electrical conductivity.

11. The solid-state battery according to claim 1, characterized in that the solid-state battery is a lithium-ion solid-state battery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following text, the suggested solid-state battery will be explained again in greater detail with reference to an exemplary embodiment in conjunction with the drawings. In the drawings:

(2) FIG. 1 is a schematic representation of the structure of a battery cell of the suggested solid-state battery;

(3) FIG. 2 shows a measurement of the dynamic differential calorimetry of the mixtures of camphor and 2-adamantanone with a lithium salt (LiTFSI, lithium bis(trifluoromethylsulfonyl)imide); and

(4) FIG. 3 shows a measurement of the ionic conductivities of the mixtures of camphor and 2-adamantanone with a lithium salt (LiTFSI, lithium bis(trifluoromethylsulfonyl)imide) as a function of temperature.

WAYS TO IMPLEMENT THE INVENTION

(5) FIG. 1 shows a highly schematic diagram of the structure of a battery cell of the suggested solid-state battery for exemplary purposes. The battery cell is composed in known manner of the cathode 1 and the anode 3, between which the solid electrolyte 2 is embedded. In the solid-state battery as shown, the solid electrolyte 2 consists of a solid matrix of camphor or 2-adamantanone in which the lithium salts (e.g., LiTFSI, LiBETI, LiAsF.sub.6, LiSF.sub.4, LiFSI, LiTfO, LiClO.sub.4, LiPF.sub.6 or LiBOB) are included. For production purposes, camphor or 2-adamantanone are suspended and mixed with lithium salts in a solvent (e.g., acetone or tetrahydrofuran (THF)), the solvent subsequently being removed again.

(6) The anode 3 may be constructed for example as a composite electrode from a layer 7 made up of anode active materials such as graphite or LTO, carbon and a polymer binder to which preferably camphor or 2-adamantanone and conducting salt is added, and a current collector 6 made of copper. The cathode 1 may be made for example from a layer of active material (e.g., LFP, LCO, LMO, NMC or NCA) and carbon, to which preferably camphor or 2-adamantanone and conducting salt is also added, and a current collector made from aluminium 4.

(7) In the following text, two exemplary compositions of the suggested solid-state battery are described.

Example 1

(8) In order to manufacture a composite cathode, a paste is prepared from 83.0 wt % LiFePO.sub.4, 6.0 wt % carbon (Super C65), 6.0 wt % binder (PVDF), 4.5 wt % camphor and 1.5 wt % LiTFSI in acetone, deposited as a coating on an aluminium foil, dried and calendered. The paste for the composite anode consists of 82.0 wt % graphite, 6.0 wt % carbon (Super C65), 6.0 wt % binder (PVDF), 4.5 wt % camphor and 1.5 wt % LiTFSI in acetone. This paste is applied in a layer to a copper foil and is also dried and calendered. The electrolyte is produced by uniaxial compression. For this, 75 wt % camphor is mixed with 25 wt % LiTFSI in acetone and this is dried and compressed to a thickness of 100 μm.

Example 2

(9) In order to manufacture a composite cathode, a paste is prepared from 83.0 wt % LiFePO.sub.4, 6.0 wt % carbon (Super C65), 6.0 wt % binder (PTFE), 4.5 wt % 2-adamantanone and 1.5 wt % LiTFSI in THF, deposited as a coating on an aluminium foil, dried and calendered. The paste for the composite anode consists of 82.0 wt % graphite, 6.0 wt % carbon (Super C65), 6.0 wt % binder (PTFE), 4.5 wt % 2-adamantanone and 1.5 wt % LiTFSI in THF. This paste is applied in a layer to a copper foil and is also dried and calendered. The electrolyte is produced by uniaxial compression. For this, 75 wt % 2-adamantanone is mixed with 25 wt % LiTFSI in THF and this is dried and compressed to a thickness of 100 μm

(10) FIGS. 2 and 3 respectively show measurements of the dynamic differential calorimetry (FIG. 2) and of the ionic conductivities as a function of temperature (FIG. 3) for mixtures of camphor and 2-adamantanone with LiTFSI. From these measurements, it is apparent that both mixtures are thermally stable and good ionic conductors in the temperature range that is significant for the battery application, from −20° C. to 60° C.

REFERENCE LIST

(11) 1 Cathode 2 Solid electrolyte 3 Anode 4 Cathodic current collector 5 Cathode composite layer 6 Anodic current collector 7 Anode composite layer