Weak-solvation non-aqueous electrolyte and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrochemical energy storage, and discloses a weak-solvation non-aqueous electrolyte as well as a preparation method and application thereof. According to the weak solvation non-aqueous electrolyte, 1-methylimidazole is used as a solvent, and zinc bis (trifluoromethane sulfonimide) is used as a soluble salt. Zn < 2 + > forms a solvation structure of Zn (EMI) 4.99 (TFSI) 1.01 in the electrolyte. Along with the progress of an electrochemical reaction process, TFSIanions are preferentially reduced and decomposed, and an organic-inorganic hybrid double-layer SEI film rich in inorganic components such as ZnF2, ZnS and ZnNx is formed on the surface of a zinc negative electrode, so that the problems of hydrogen evolution side reaction and zinc dendrite existing in an aqueous electrolyte are effectively avoided, and efficient and reversible deposition / stripping of Zn < 2 + > is realized. The zinc ion battery using the electrolyte shows ultra-long cycle life, ultra-low overpotential, high coulombic efficiency and wide temperature adaptability, and a new solution is provided for practical application of the zinc ion battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrochemical energy storage, and particularly relates to a weakly solvated non-aqueous electrolyte and a preparation method and application thereof. BACKGROUND

[0002] Rechargeable batteries based on multivalent metal anodes have attracted extensive attention, and among various multivalent metal anodes, rechargeable zinc ion batteries have become one of the most promising candidates for the next generation of energy storage devices due to the high theoretical specific capacity, low redox potential, good cost-effectiveness, and environmental friendliness of zinc anodes. Among various rechargeable zinc ion batteries, aqueous zinc ion batteries are the most widely used type.

[0003] However, in aqueous zinc ion batteries, the following two problems exist: on the one hand, the thermodynamic instability of the metal zinc anode can lead to uneven deposition of zinc ions at the anode interface, further forming zinc dendrites. On the other hand, Zn(H2O)6 2+ The formation of solvated structures inevitably causes serious hydrogen evolution reactions and the formation of ZnO, Zn(OH)4 2- and other byproducts. These key problems can further cause instability of the zinc / electrolyte interface, low coulombic efficiency of zinc deposition / detachment, decomposition of the electrolyte, and other problems, ultimately resulting in poor cycle performance and capacity decay of the entire battery.

[0004] In order to construct a high-performance zinc ion battery system, non-aqueous electrolytes are considered to be an effective way to solve the above problems of aqueous electrolytes. However, most organic solvents can form strong bidentate or multidentate coordination structures with zinc ions through donor oxygen atoms, significantly hindering the desolvation kinetics, leading to unnecessary overpotential during zinc deposition, and also not conducive to the formation of a stable solid electrolyte interface (SEI). Therefore, it is of great significance to develop a non-aqueous electrolyte that can construct a weak solvation structure, promote anions to participate in the solvation sheath, and achieve efficient desolvation of zinc ions. SUMMARY

[0005] To solve the problems in the prior art, the purpose of the present application is to provide a weakly solvated non-aqueous electrolyte and a preparation method and application thereof, which can construct a weak solvation structure, promote anions to participate in the solvation sheath, and achieve efficient desolvation of zinc ions.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: A weakly solvated non-aqueous electrolyte, comprising 1-methylimidazole as a solvent and bis-trifluoromethanesulfonylimide zinc as a solute, wherein the concentration of the bis-trifluoromethanesulfonylimide zinc is 0.2-0.3 mol / L.

[0007] Preferably, in the weakly solvated non-aqueous electrolyte, the solvated structure of Zn 2+ is Zn(EMI) 4.99 (TFSI) 1.01 , wherein EMI represents 1-methylimidazole, and TFSI represents zinc bis(trifluoromethanesulfonyl)imide.

[0008] The application also provides a preparation method of the weakly solvated non-aqueous electrolyte as described above, comprising the following steps: adding zinc bis(trifluoromethanesulfonyl)imide into 1-methylimidazole, and stirring until the zinc bis(trifluoromethanesulfonyl)imide is dissolved to obtain the weakly solvated non-aqueous electrolyte.

[0009] Preferably, the zinc bis(trifluoromethanesulfonyl)imide is added into 1-methylimidazole, and stirred at 20-30°C until the zinc bis(trifluoromethanesulfonyl)imide is dissolved.

[0010] The weakly solvated non-aqueous electrolyte as described above is used as an electrolyte of a rechargeable zinc ion battery.

[0011] Preferably, the rechargeable zinc ion battery is a Zn||Zn symmetric battery, a Zn||Cu asymmetric battery, or a Zn||LiFePO4 full battery.

[0012] Preferably, the solid electrolyte interface formed on the surface of the zinc negative electrode has an organic-inorganic hybrid double-layer structure, the outer layer contains organic components, and the inner layer contains ZnF2, ZnS, and ZnN x inorganic components.

[0013] Preferably, the Zn||Zn symmetric battery has a cycle life of more than 7900 hours and an overpotential of 20 mV at a current density of 0.5 mA cm –2 .

[0014] Preferably, the average coulombic efficiency of the Zn||Cu asymmetric battery is more than 99.43%.

[0015] Preferably, the LiFePO4 pole piece is obtained by uniformly mixing LiFePO4, polyvinylidene fluoride, and conductive carbon black in a ratio of (7-9):1:1, and then coating the mixed slurry on a titanium foil and drying. The weakly solvated non-aqueous electrolyte as described above is added with lithium trifluoromethanesulfonylimide, and the lithium trifluoromethanesulfonylimide is dissolved to obtain an electrolyte for a Zn||LiFePO4 full battery, wherein the concentration of the lithium trifluoromethanesulfonylimide is 0.4-0.5 M. A Zn||LiFePO4 full battery is obtained by assembling a zinc foil as a negative electrode, LiFePO4 as a positive electrode, and the electrolyte for the Zn||LiFePO4 full battery. The Zn||LiFePO4 full battery has a capacity retention rate of 50% or more after 100 cycles at a current density of 0.05 A g –1

[0016] The application has the following beneficial effects: In the weakly solvated non-aqueous electrolyte of the application, the EMI (1-methylimidazole) solvent molecules form weakly coordinated Zn-N bonds with Zn 2+ , changing the strong Zn-O coordination bond in traditional solvents. At the same time, a high proportion of TFSI – anions (trifluoromethanesulfonylimide anions) enter the solvation sheath, so that during zinc deposition, TFSI – anions are preferentially reduced and decomposed, forming an organic-inorganic hybrid double-layer SEI film rich in inorganic components such as ZnF2, ZnS and ZnN x on the surface of the zinc anode. The organic components in the SEI layer effectively alleviate the volume change of the electrode during the electrochemical reaction, ensuring the stability of the SEI film structure. This double-layer SEI structure effectively suppresses the hydrogen evolution side reaction and zinc dendrite growth, achieving efficient and reversible deposition / stripping of zinc ions. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1(a) is an impedance test of the electrolyte prepared in Example 1 of the application at different temperatures; Figure 1(b) is the ionic conductivity of the electrolyte prepared in Example 1 calculated from the impedance test; Figure 2(a) is a characterization of the Zn 2+ solvation structure in the non-aqueous electrolyte of Example 1 of the application: molecular dynamics simulation snapshot; Figure 2(b) is a characterization of the Zn 2+ solvation structure in the non-aqueous electrolyte of Example 1 of the application: radial distribution function; Figure 3 is the electrochemical stability window of the non-aqueous electrolyte of Example 1 of the application at different temperatures; Figure 4 is the cycle life of the Zn||Zn symmetric battery prepared using Example 2 of the application; Figure 5 is a comparison of the cycle performance of the Zn||Zn symmetric battery prepared using Example 2 of the application at different temperatures; Figure 6 is the coulombic efficiency of the Zn||Cu asymmetric battery prepared using Example 3 of the application; ​Figure 7(a) is an XPS spectrum of F1s in the interface SEI of the zinc negative electrode in the Zn||Zn symmetric battery prepared in Example 2 of the present application; Figure 7(b) is an XPS spectrum of S2p in the interface SEI of the zinc negative electrode in the Zn||Zn symmetric battery prepared in Example 2 of the present application; Figure 7(c) is an XPS spectrum of N1s in the interface SEI of the zinc negative electrode in the Zn||Zn symmetric battery prepared in Example 2 of the present application; Figure 8(a) is the cycle performance of the Zn||LiFePO4 full battery prepared in Example 4 of the present application; Figure 8(b) is the rate performance of the Zn||LiFePO4 full battery prepared in Example 4 of the present application; Figure 9 The electrolyte obtained in Example 1, Example 5 and Comparative Example 1 of the present application is used to test the ion conductivity at different concentrations in a three-electrode system, and the comparison chart is shown in Figure 1; Figure 10 The Zn||Zn symmetric battery of Example 6 of the present application is cycled at a current density of 0.5 mA cm –2 and an area capacity of 0.5 mAh cm –2 , and the cycle test result chart is shown in Figure 6. Figure 11 The Zn||Zn symmetric battery of Comparative Example 2 of the present application is cycled at a current density of 0.5 mA cm –2 and an area capacity of 0.5 mAh cm –2 , and the cycle test result chart is shown in Figure 7. DETAILED DESCRIPTION

[0018] The present application will be described below in conjunction with the accompanying drawings and examples, which are only used to explain the present application and are not intended to limit the scope of the present application.

[0019] The present application provides a weakly solvated non-aqueous electrolyte, which comprises 1-methylimidazole (EMI) and zinc bis-trifluoromethanesulfonimide (Zn(TFSI)2), wherein the solvated structure of Zn 2+ is Zn(EMI) 4.99 (TFSI) 1.01 In the electrolyte, EMI serves as a solvent, and Zn(TFSI)2 serves as a solute, and the concentration of Zn(TFSI)2 is 0.2-0.3 mol / L, preferably 0.3M.

[0020] The solid electrolyte interface (SEI) formed by the electrolyte on the surface of the zinc negative electrode is an organic-inorganic hybrid double-layer structure, the outer layer is mainly organic components, and the inner layer is rich in ZnF2, ZnS and ZnN x inorganic components.

[0021] The working principle of the weakly solvated non-aqueous electrolyte of the present application is as follows: In the weak-solvation non-aqueous electrolyte, EMI solvent molecules coordinate with Zn 2+ to form weakly coordinated Zn-N bonds, changing the strong Zn-O coordination bonds in traditional solvents. Meanwhile, a high proportion of TFSI – anions enter the solvation sheath, so that during zinc deposition, TFSI – anions are preferentially reduced and decomposed to form an organic-inorganic hybrid bilayer SEI film rich in ZnF2, ZnS and ZnN x and other inorganic components on the surface of the zinc anode. The organic components in the SEI layer effectively alleviate the volume change of the electrode during the electrochemical reaction, ensuring the stability of the SEI film structure. This bilayer SEI structure effectively suppresses the hydrogen evolution side reaction and zinc dendrite growth, achieving efficient and reversible deposition / stripping of zinc ions.

[0022] The preparation process of the above-mentioned weak-solvation non-aqueous electrolyte of the present application is as follows: Zn(TFSI)2 is added to the EMI solvent and stirred at room temperature until completely dissolved, to prepare a weak-solvation non-aqueous electrolyte with a concentration of 0.2-0.3 M.

[0023] Example 1: The preparation process of the weak-solvation non-aqueous electrolyte of this example is as follows: Zn(TFSI)2 salt is slowly added to the EMI solvent and stirred at room temperature until completely dissolved, to prepare a weak-solvation non-aqueous electrolyte with a concentration of 0.3 M.

[0024] The impedance test results of the electrolyte prepared in this example at different temperatures are shown in Figure 1(a), and the impedances at 25℃-80℃ are 191.74 Ω, 148.99 Ω, 100.63 Ω and 77.91 Ω, respectively. The ionic conductivity of the electrolyte of this example calculated according to the impedance test results is shown in Figure 1(b), and is 15.4, 19.6, 29.0 and 38.1 mS·cm –1 , respectively. 2+ The characterization of the solvation structure (molecular dynamics simulation snapshot) of this example is shown in Figure 2(a), and the solvation structure is mainly composed of Zn 2+ , EMI and TFSI – . 2+ The characterization of the solvation structure (radial distribution function) of this example is shown in Figure 2(b), and one Zn 2+ is coordinated by 4.99 EMI molecules and 1.01 TFSI – . Figure 3As shown, the voltage window at 25 ℃ is 2.43 V, and when the temperature reaches 80 ℃, the voltage window still remains at 2.25 V.

[0025] Example 2: Assembly and Testing of Zn||Zn Symmetric Cells Using zinc foil as the positive and negative electrodes, and employing the 0.3 M weakly solvated non-aqueous electrolyte prepared in Example 1, a Zn||Zn symmetric cell was assembled in a glove box. The electrolyte was measured at 0.5 mA cm⁻¹. –2 The current density and 0.25 mAh cm⁻¹ –2 Cyclic testing was conducted under the area capacity.

[0026] The cycle life of the Zn||Zn symmetric cell prepared in this embodiment is as follows: Figure 4 As shown, it can achieve 0.5 mA cm –2 The Zn||Zn symmetric cell prepared in this embodiment was stably cycled for 7900 h at a current density. The cycling performance of the Zn||Zn symmetric cell at different temperatures is compared as follows: Figure 5 As shown, the polarization overpotential gradually decreases with increasing temperature and can cycle stably at temperatures ranging from 25 to 80 °C.

[0027] Electrode interface characterization The XPS spectrum of F1s in the SEI interface of the Zn||Zn symmetric solar cell prepared in this embodiment is shown in Figure 7(a). With the increase of etching depth, the content of the organic species -CF3 decreased from 92.49% to 25.73%, while the content of ZnF2 increased from 7.51% to 74.27%. The XPS spectrum of S2p in the SEI interface of the Zn||Zn symmetric solar cell prepared in this embodiment is shown in Figure 7(b). The content of the organic species SO2-C decreased from 100% to 30.86%, while the content of ZnS increased from 7.51% to 74.27%. The XPS spectrum of N1s in the SEI interface of the Zn||Zn symmetric solar cell prepared in this embodiment is shown in Figure 7(c). The organic species N + The contents of Zn and CN decreased from 18.04% and 81.96% to 8.44% and 44.18%, respectively, while the inorganic species ZnN... x The content increased to 47.38%.

[0028] Example 3: Assembly and Testing of Zn||Cu Asymmetric Cells A Zn||Cu asymmetric cell was assembled using zinc foil as the negative electrode and copper foil as the positive electrode, employing the 0.3 M weakly solvated non-aqueous electrolyte prepared in Example 1. The electrolyte was used at 0.5 mA cm⁻¹. –2 The current density and 0.5 mAh cm⁻¹ –2The coulombic efficiency of zinc deposition / stripping was calculated based on the area capacity test.

[0029] The coulombic efficiency of the Zn||Cu asymmetric battery prepared in this embodiment is as follows: Figure 6 As shown, the Coulomb efficiency is 99.43%.

[0030] Example 4: Preparation of LiFePO4 electrode Commercially available LiFePO4 was mixed with polyvinylidene fluoride (PVDF) and conductive carbon black (SuperP) in a ratio of 8:1:1. The uniformly mixed slurry was then coated onto titanium foil with a scraper and dried at 70°C to obtain LiFePO4 electrode sheets.

[0031] Assembly and Testing of Zn||LiFePO4 Full Cells Lithium trifluoromethanesulfonylimide was added to the weakly solvated non-aqueous electrolyte prepared in Example 1 to dissolve the lithium trifluoromethanesulfonylimide, thereby obtaining an electrolyte for Zn||LiFePO4 full cells, wherein the concentration of lithium trifluoromethanesulfonylimide was 0.5M. A Zn||LiFePO4 full cell was assembled using zinc foil as the negative electrode and LiFePO4 as the positive electrode, along with the electrolyte. The cycle and rate performance of the cell were tested using a Blue Electric testing system.

[0032] The cycling performance of the Zn||LiFePO4 full cell in this embodiment is shown in Figure 8(a), where the red spheres represent specific capacity and the blue spheres represent coulombic efficiency, achieving a cycle performance of 50 mA g. –1 After 100 stable cycles at a current density, the capacity retention rate is close to 50%. The rate performance of the Zn||LiFePO4 full cell in this embodiment is shown in Figure 8(b), where the red spheres represent specific capacity and the blue spheres represent coulombic efficiency at 0.01 A g. –1 The discharge specific capacity is 130.6 mAh g. –1 At 0.1 Ag –1 The discharge specific capacity is 64.9 mAh g. – 1. When restored to 0.01 Ag –1 At that time, the discharge capacity almost recovered to its original level. The red sphere represents specific capacity, and the blue sphere represents coulombic efficiency. Example 5: The preparation process of the weakly solvated non-aqueous electrolyte in this embodiment is as follows: 0.12513 g of Zn(TFSI)2 salt was slowly added to 1 mL of EMI solvent and stirred at room temperature until completely dissolved to prepare a weakly solvated non-aqueous electrolyte with a concentration of 0.2 M.

[0033] Example 6: Assembly and test of Zn||Zn symmetric battery A Zn||Zn symmetric battery was assembled in a glove box using zinc foil as the positive and negative electrodes and the 0.2M non-aqueous electrolyte prepared in Example 5. The cyclic test was carried out at a current density of 0.5 mA cm –2 and an area capacity of 0.25 mAh cm –2 . The test results are shown in Figure 10 , and the Zn||Zn symmetric battery can be stably cycled for 5000 h at a current density of 0.5 mA cm –2 .

[0034] Preparation process of the weakly solvated non-aqueous electrolyte in Comparative Example 1 is as follows: 0.25026 g of Zn(TFSI)2 salt was slowly added to 1 mL of EMI solvent, and stirred at room temperature until completely dissolved to prepare a weakly solvated non-aqueous electrolyte with a concentration of 0.4M.

[0035] The ion conductivities of the electrolytes obtained in Example 1, Example 5 and Comparative Example 1 were tested using a three-electrode system, and the comparison chart is shown in Figure 9 . When the electrolyte concentration is 0.2M, the EMI electrolyte exhibits a low ion conductivity, and the ion conductivity is 7.53 mS cm –1 at 20°C. –1 When the concentration is increased to 0.3M, the ion conductivity is 15.4 mS cm –1 .

[0036] Comparative Example 2: Assembly and test of Zn||Zn symmetric battery A Zn||Zn symmetric battery was assembled in a glove box using zinc foil as the positive and negative electrodes and the 0.4M non-aqueous electrolyte prepared in Comparative Example 1. The cyclic test was carried out at a current density of 0.5 mA cm –2 and an area capacity of 0.5 mAh cm –2 . The test results are shown in Figure 11 , and the Zn||Zn symmetric battery can be stably cycled for only about 1100 h.

[0037] In summary, the present application has the following characteristics: Excellent ion conductivity: the EMI electrolyte prepared can achieve a high ion conductivity of 15.4 mS cm –1 at room temperature.

[0038] Wide voltage window: The prepared EMI electrolyte realizes a high voltage window of 2.43 V.

[0039] Anion-rich solvation structure: The solvation structure of zinc ions in the electrolyte is Zn(EMI) 4.99 (TFSI) 1.01 , realizing a high proportion of anions participating in the construction of the solvation structure.

[0040] Double-gradient SEI: A double-gradient SEI layer is formed on the surface of the Zn negative electrode, with the outer layer dominated by organic components and the inner layer dominated by inorganic components, ensuring excellent electrochemical performance of the subsequent zinc negative electrode.

[0041] Ultra-long cycle life: The Zn||Zn symmetric battery using the electrolyte has a cycle life of more than 7900 hours (about 11 months) at a current density of 0.5 mA cm –2 .

[0042] Ultra-low overpotential: The overpotential of the Zn 2+ deposition / stripping process is as low as 20 mV, significantly reducing the energy barrier in the Zn 2+ deposition / stripping process.

[0043] High coulombic efficiency: The average coulombic efficiency of the Zn||Cu asymmetric battery is as high as 99.43%, indicating that the utilization efficiency of zinc ions is extremely high.

[0044] Wide temperature adaptability: The electrolyte can work stably in a temperature range of 25℃ to 80℃, widening the application scenarios of the battery.

[0045] Good compatibility with positive electrode materials: Compatible with commercial positive electrode materials such as LiFePO4, the Zn||LiFePO4 full battery constructed shows excellent electrochemical performance.

[0046] In the present invention, Zn 2+ forms a solvation structure of Zn(EMI) 4.99 (TFSI) 1.01 in the electrolyte. With the progress of electrochemical reactions, TFSI⁻ anions are preferentially reduced and decomposed, forming an organic-inorganic hybrid double-layer SEI film rich in inorganic components such as ZnF2, ZnS and ZnN x on the surface of the zinc negative electrode, effectively avoiding the hydrogen evolution side reaction and zinc dendrite problem existing in aqueous electrolyte, realizing the efficient and reversible deposition / stripping of Zn 2+ .

[0047] Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should belong to the protection scope of the present application.

[0048] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Although the present application has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A weakly solvated non-aqueous electrolyte, characterized in that, It includes 1-methylimidazole as a solvent and zinc bis(trifluoromethanesulfonyl)imide as a solute, wherein the concentration of zinc bis(trifluoromethanesulfonyl)imide is 0.2-0.3 mol / L.

2. The weakly solvated non-aqueous electrolyte according to claim 1, characterized in that, In the weakly solvated non-aqueous electrolyte, Zn 2+ The solvated structure is Zn(EMI). 4.99 (TFSI) 1.01 EMI stands for 1-methylimidazole, and TFSI stands for zinc bis(trifluoromethanesulfonylimide).

3. The method for preparing a weakly solvated non-aqueous electrolyte according to claim 1 or 2, characterized in that, The process includes the following: Zinc bis(trifluoromethanesulfonyl)imide was added to 1-methylimidazole and stirred until the zinc bis(trifluoromethanesulfonyl)imide dissolved to obtain the weakly solvated non-aqueous electrolyte.

4. The method for preparing a weakly solvated non-aqueous electrolyte according to claim 3, characterized in that, Add zinc bis(trifluoromethanesulfonyl)imide to 1-methylimidazole and stir at 20-30°C until the zinc bis(trifluoromethanesulfonyl)imide dissolves.

5. The application of the weakly solvated non-aqueous electrolyte according to claim 1 or 2, characterized in that, The weakly solvated non-aqueous electrolyte is used as the electrolyte in a rechargeable zinc-ion battery.

6. The application of the weakly solvated non-aqueous electrolyte according to claim 5, characterized in that, The rechargeable zinc-ion battery is a Zn||Zn symmetric cell, a Zn||Cu asymmetric cell, or a Zn||LiFePO4 full cell.

7. The application of the weakly solvated non-aqueous electrolyte according to claim 6, characterized in that, The solid electrolyte interface formed on the zinc anode surface is an organic-inorganic hybrid bilayer structure, with the outer layer containing organic components and the inner layer containing ZnF2, ZnS, and ZnN. x Inorganic components.

8. The application of the weakly solvated non-aqueous electrolyte according to claim 6, characterized in that, The Zn||Zn symmetric cell at 0.5 mA cm⁻¹ –2 At a current density of 7900 hours, the cycle life is over 7900 hours and the overpotential is 20 mV.

9. The application of the weakly solvated non-aqueous electrolyte according to claim 6, characterized in that, The average coulombic efficiency of the Zn||Cu asymmetric cell is above 99.43%.

10. The application of the weakly solvated non-aqueous electrolyte according to claim 6, characterized in that: After uniformly mixing LiFePO4 with polyvinylidene fluoride and conductive carbon black in a ratio of (7-9):1:1, a mixed slurry is obtained. The mixed slurry is coated on titanium foil and dried to obtain LiFePO4 electrode sheets. Lithium trifluoromethanesulfonylimide is added to the weakly solvated non-aqueous electrolyte according to claim 1 or 2 to dissolve the lithium trifluoromethanesulfonylimide, thereby obtaining an electrolyte for Zn||LiFePO4 full cells, wherein the concentration of lithium trifluoromethanesulfonylimide is 0.4-0.5M; A Zn||LiFePO4 full cell was assembled using zinc foil as the negative electrode and LiFePO4 as the positive electrode, and the Zn||LiFePO4 full cell was assembled with electrolyte. The Zn||LiFePO4 full cell at 0.05 A g –1 At current densities, the capacity retention rate is over 50% after 100 cycles.

Images