A recyclable PCFC cathode material and its preparation method and recycling method

Abstract

The present invention belongs to the technical field of new energy solid oxide fuel cells, and specifically relates to a recyclable PCFC cathode material and a preparation method and a recycling method thereof. The present invention aims at the technical problems that the existing proton ceramic fuel cell (PCFC) cathode material has poor matching with common electrolyte materials, is easy to detach, causes battery performance degradation, and lacks a complete PCFC cathode recycling technology. The present invention provides a new type of recyclable PCFC cathode material and a preparation method and a recycling method thereof. The new type of PCFC cathode material has the advantages of high activity and recyclability. The recycling method is simple to operate, has low energy consumption, and the recovery rate can theoretically reach 100%, which is easy to promote and use.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy solid oxide fuel cells, and specifically relates to a recyclable proton ceramic fuel cell (PCFC) cathode material and a preparation method and a recycling method thereof. Background Art

[0002] Proton ceramic fuel cell (PCFC) is a new type of power generation technology with the advantages of high energy conversion efficiency and environmental friendliness. At present, cathode materials are one of the main factors limiting the application of this technology, and related research has received widespread attention. The cathode of PCFC requires a certain proton, oxygen ion and electron conductivity, and a certain degree of matching with the electrolyte material. On the one hand, there is currently a lack of cathode materials that can fully match PCFC. The existing PCFC cathode materials have poor matching with common electrolyte materials and are easy to detach, causing battery performance to decay. On the other hand, there is still a lack of complete PCFC cathode recycling technology. These increase the material cost of the battery and limit the further application of this technology.

[0003] In addition, the waste fuel cells are discarded at random, which will cause waste of resources and environmental pollution. Therefore, developing a recyclable cathode material and a recycling method thereof has become a technical problem that needs to be solved in this field. Summary of the invention

[0004] In view of this, in order to solve the problems existing in the prior art, the present invention provides a new type of recyclable PCFC cathode material and a preparation method and a recycling method thereof. The new type of PCFC cathode material has the advantages of high activity and recyclability. The recycling method is simple to operate and has low energy consumption. The recovery rate can theoretically reach 100%, and it is easy to promote and use.

[0005] In order to achieve the above objectives, the first objective of the present invention is to provide a recyclable PCFC cathode material, which adopts the following technical solution:

[0006] A recyclable PCFC cathode material with the chemical formula Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 ) 6-δ .

[0007] It is worth noting that the PCFC cathode material Ba disclosed in the present invention 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5)O6 can generate single perovskite and double perovskite phases in situ, which is helpful for improving catalytic activity and implementing material recycling. In addition, double perovskite has better ionic conductivity, and single perovskite has small particles and high dispersion, which can improve the catalytic activity of the catalyst.

[0008] And, the second object of the present invention is to provide a method for preparing a recyclable PCFC cathode material as described above.

[0009] A method for preparing a recyclable PCFC cathode material comprises the following steps:

[0010] (1) According to the cathode material Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 ) 6-δ According to the stoichiometric ratio, accurately weigh BaCO3, La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O and set aside;

[0011] (2) BaCO3 was dissolved in 5 mol / L nitric acid solution, and then La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O were added in sequence and mixed well. Subsequently, glycine and citric acid were added as complexing agents. The mixed solution was evaporated at 90°C to obtain a gel.

[0012] (3) heating the gel obtained in step (2) at 250°C for 2 h to obtain a powder;

[0013] (4) Sintering the powder obtained in step (3) at 1000-1150° C. for 3 h to obtain cathode powder, which is a recyclable PCFC cathode material.

[0014] It is worth noting that the one-step method for preparing recyclable PCFC cathode materials disclosed in the present invention can simultaneously produce two composite catalysts, single perovskite and double perovskite. The in-situ generation of the composite catalyst helps to improve the contact between the cathode layer and the electrolyte layer and enhance its matching degree with the electrolyte material. In addition, the additional substances generated during the recycling process can be absorbed by the single perovskite and double perovskite, avoiding the generation of impurities, which is beneficial to the improvement of battery performance, thereby facilitating the recycling of the battery, and helping to improve the catalytic activity and the implementation of material recycling.

[0015] Furthermore, in step (2), the amount of glycine is 2-3 times the total molar amount of metal ions, and the amount of citric acid is 1.5-2 times the total molar amount of metal ions.

[0016] And, the third object of the present invention is to provide a method for recycling the recyclable PCFC cathode material as described above.

[0017] A method for recycling recyclable PCFC cathode materials comprises the following steps:

[0018] (1) containing the recyclable PCFC cathode material Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 ) 6-δ Manually dismantle the waste batteries to obtain waste cathode materials;

[0019] (2) The waste cathode material was crushed in an agate mortar and ball-milled at 400 rpm for 3-5 h, and a 0.5-1.0 mol / L dilute nitric acid solution was prepared. The cathode powder was added to the dilute nitric acid solution for washing at a weight ratio of concentrated nitric acid to powder of 3-5 wt%, thereby obtaining cathode powder A;

[0020] (3) The cathode powder A obtained in step (2) was ball-milled at 400 rpm for 3-5 h, and then sintered at 1100 °C for 3-5 h to obtain cathode powder B;

[0021] (4) The cathode powder B obtained in step (3) was ball-milled at 400 rpm for 2 h to obtain regenerated cathode powder C.

[0022] Considering that there is currently no complete recovery method for solid oxide fuel cell cathode materials, the present invention designs a composite catalyst cathode and uses an acid washing method to improve the surface activity of the cathode material, thereby effectively improving the regeneration performance of the solid oxide fuel cell cathode material.

[0023] Compared with the traditional PCFC cathode, the recyclable PCFC cathode material Ba prepared by the one-step synthesis method in the present invention 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5)O6, single perovskite and double perovskite phases can be generated in situ, which helps to improve the contact between the cathode layer and the electrolyte layer and enhance its matching with the electrolyte material. At the same time, the two phases generated in situ are expected to facilitate the recycling of the battery. The additional substances generated during the recycling process will most likely be absorbed by the single perovskite and double perovskite, avoiding the generation of impurities, which is beneficial to the improvement of battery performance, thereby helping to improve catalytic activity and the implementation of material recycling. The above-mentioned recycling technology method can realize the reconstruction of PCFC cathode materials, which helps to improve battery performance. In addition, the recycling method disclosed in the present invention is simple to operate, has low energy consumption, and the recovery rate can theoretically reach 100%, which is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 The present invention is a process flow chart of the preparation method and recovery method of the recyclable PCFC cathode material.

[0026] Figure 2 This is the XRD comparison diagram of the cathode (from bottom to top) before recovery, acid-washed powder and after recovery in Experimental Example 1 of the present invention.

[0027] Figure 3 This is a SEM morphology image of the recovered front cathode powder in Experimental Example 1 of the present invention.

[0028] Figure 4 This is the SEM morphology of the acid-washed powder in Experimental Example 1 of the present invention.

[0029] Figure 5 This is a SEM morphology of the cathode layer after recovery in Experimental Example 1 of the present invention.

[0030] Figure 6 This is a SEM image of the cross section of the whole battery after recovery in Experimental Example 2 of the present invention.

[0031] Figure 7 It is the power density of the battery before recycling in Experimental Example 2 of the present invention.

[0032] Figure 8 It is the power density of the battery after recycling in Experimental Example 2 of the present invention.

[0033] Fig. 9 This is a comparison diagram of the polarization resistance of the battery before and after recycling in Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0036] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0037] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0038] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0039] The present invention discloses a recyclable PCFC cathode material and a preparation method and a recycling method thereof, and belongs to the technical field of new energy solid oxide fuel cells. The present invention aims at the technical problems that the existing PCFC cathode material has poor matching degree with common electrolyte materials, is easy to separate, causes battery performance attenuation, and lacks a complete PCFC cathode recycling technology, and provides a new type of recyclable PCFC cathode material and a preparation method and a recycling method thereof. The new type of PCFC cathode material has the advantages of high activity and recyclability, and the recycling method is simple to operate, low in energy consumption, and the recovery rate can theoretically reach 100%, which is easy to promote and use.

[0040] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0041] Example 1

[0042] A recyclable PCFC cathode material and preparation method thereof:

[0043] (1) According to the cathode material Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 )O6 (BGLCF) weighs BaCO3, La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O in the stoichiometric ratio;

[0044] (2) BaCO3 was dissolved in 5 mol / L nitric acid solution, and then La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O were added in sequence and mixed well. Then glycine and citric acid were added as complexing agents, where the metal ion: glycine: citric acid (molar ratio) was 1:1.5:1. The mixed solution was evaporated at 90 °C to obtain a gel.

[0045] (3) heating the gel obtained in step (2) at 250°C for 2 h to obtain a powder;

[0046] (4) Sintering the powder obtained in step (3) at 1000 degrees for 3 hours to obtain a recyclable BGLCF cathode material.

[0047] A method for recycling recyclable PCFC cathode materials:

[0048] (1) Manually dismantle the waste batteries to obtain waste cathode materials;

[0049] (2) The waste cathode material was crushed in an agate mortar and ball-milled at 400 rpm for 3-5 h, and a 0.5 / L dilute nitric acid solution was prepared, with a weight ratio of concentrated nitric acid to powder of 3%, and the cathode powder was added to the dilute nitric acid solution for washing to obtain cathode powder A;

[0050] (3) The cathode powder A obtained in step (2) was ball-milled at 400 rpm for 3-5 h, and then sintered at 1100 °C for 3-5 h to obtain cathode powder B;

[0051] (4) The cathode powder B obtained in step (3) was ball-milled at 400 rpm for 2 h to obtain regenerated cathode powder C.

[0052] Example 2

[0053] A recyclable PCFC cathode material and preparation method thereof:

[0054] (1) According to the cathode material Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 )O6 (BGLCF) weighs BaCO3, La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O in the stoichiometric ratio;

[0055] (2) BaCO3 was dissolved in 5 mol / L nitric acid solution, and then La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O were added in sequence and mixed well. Then glycine and citric acid were added as complexing agents, where the metal ion: glycine: citric acid (molar ratio) was 1:1.5:1. The mixed solution was evaporated at 90 °C to obtain a gel.

[0056] (3) heating the gel obtained in step (2) at 250°C for 2 h to obtain a powder;

[0057] (4) The powder obtained in step (3) is sintered at 1050 degrees for 3 hours to obtain cathode powder, BGLCF cathode material.

[0058] A method for recycling recyclable PCFC cathode materials:

[0059] (1) Manually dismantle the waste batteries to obtain waste cathode materials;

[0060] (2) The waste cathode material was crushed in an agate mortar and ball-milled at 400 rpm for 3-5 h, and a 0.5 / L dilute nitric acid solution was prepared, with a weight ratio of concentrated nitric acid to powder of 5%, and the cathode powder was added to the dilute nitric acid solution for washing to obtain cathode powder A;

[0061] (3) The cathode powder A obtained in step (2) was ball-milled at 400 rpm for 3-5 h, and then sintered at 1100 °C for 3-5 h to obtain cathode powder B;

[0062] (4) The cathode powder B obtained in step (3) was ball-milled at 400 rpm for 2 h to obtain regenerated cathode powder C.

[0063] Example 3

[0064] A recyclable PCFC cathode material and preparation method thereof:

[0065] (1) According to the cathode material Ba 1.1 (Gd 0.8La 0.2 ) 0.9 (Co 1.5 Fe 0.5 )O6 (BGLCF) weighs BaCO3, La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O in the stoichiometric ratio;

[0066] (2) BaCO3 was dissolved in 5 mol / L nitric acid solution, and then La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O were added in sequence and mixed well. Then glycine and citric acid were added as complexing agents, where the metal ion: glycine: citric acid (molar ratio) was 1:1.5:1. The mixed solution was evaporated at 90 °C to obtain a gel.

[0067] (3) heating the gel obtained in step (2) at 250°C for 2 h to obtain a powder;

[0068] (4) The powder obtained in step (3) is sintered at 1100 degrees for 3 hours to obtain cathode powder, BGLCF cathode material.

[0069] A method for recycling recyclable PCFC cathode materials:

[0070] (1) Manually dismantle the waste batteries to obtain waste cathode materials;

[0071] (2) The waste cathode material was crushed in an agate mortar and ball-milled at 400 rpm for 3-5 h, and a 0.5 / L dilute nitric acid solution was prepared, with a weight ratio of concentrated nitric acid to powder of 5%, and the cathode powder was added to the dilute nitric acid solution for washing to obtain cathode powder A;

[0072] (3) The cathode powder A obtained in step (2) was ball-milled at 400 rpm for 3-5 h, and then sintered at 1100 °C for 3-5 h to obtain cathode powder B;

[0073] (4) The cathode powder B obtained in step (3) was ball-milled at 400 rpm for 2 h to obtain regenerated cathode powder C.

[0074] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the properties and application performance of the recyclable PCFC cathode material and its preparation method and recycling method disclosed in the present invention are further illustrated by the following comparative examples and experimental examples, but they should not be understood as limitations of the present invention. The method properties obtained by other measurement experiments conducted by technicians in this field based on the above-mentioned invention content and the applications based on the above-mentioned properties are also regarded as falling within the protection scope of the present invention.

[0075] Experimental Example 1

[0076] The cathode before recovery, acid-washed powder and recovered cathode disclosed in Example 1 were characterized by XRD. The results are as follows: Figure 2 As shown, it can be seen that the cathode components before recycling are BGLCF and single perovskite phase ((Ba,La)(Co,Fe)O3 phase (abbreviated as BLCF), without other impurities. In addition to BGLCF, multiple impurities such as barium carbonate were observed in the acid-washed cathode XRD. In addition to the BGLCF phase and BLCF single perovskite phase, triclinic single perovskite (T phase) and Ag phase can also be observed in the recycled cathode. This shows that the Ag in the current collector is incorporated into the recycled cathode powder.

[0077] The regenerated cathode powder C obtained in Example 1, ethyl cellulose and pinene alcohol (weight ratio 1:0.06:0.94) were mixed and ball-milled. After preparing the slurry, it was coated on the half-cell to obtain a full cell. Figure 3 , Figure 4 and Figure 5 The cathode morphology before, after and after acid washing is shown in Figure 1. The cathode before and after recycling is basically the same in terms of particle size and shape. At the same time, corrosion can be observed on the surface of the acid washed cathode.

[0078] Experimental Example 2

[0079] The cross-sectional view of the recovered full battery prepared from the regenerated cathode powder C obtained in Example 2 ( Figure 6 ), which proves that the recycled cathode can also achieve good contact with the half-cell. Figure 7 The voltage-current and power density curves of the full cell assembled with the recycled cathode. Figure 8 ), the battery power density is improved to a certain extent, thanks to the use of this technical solution to achieve the doping of Ag and the emergence of T-phase single perovskite. Impedance spectrum test results ( Fig. 9 ) shows that, especially in the low temperature section, the polarization resistance value after recycling has been reduced to a certain extent.

[0080] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A recyclable PCFC cathode material, characterized in that: The chemical formula is Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 ) 6-δ ; The method for preparing the recyclable PCFC cathode material specifically comprises the following steps: (1) According to the cathode material Ba 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 ) 6-δ According to the stoichiometric ratio, accurately weigh BaCO3, La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O and set aside; (2) BaCO3 was dissolved in 5 mol / L nitric acid solution, and then La(NO3)3, Gd (NO3)3, Co(NO3)2·6H2O and Fe(NO3)3·9H2O were added in sequence and mixed well. Subsequently, glycine and citric acid were added as complexing agents. The mixed solution was evaporated at 90°C to obtain a gel. (3) heating the gel obtained in step (2) at 250°C for 2 h to obtain a powder; (4) Sintering the powder obtained in step (3) at 1000-1150° C. for 3 h to obtain cathode powder, which is a recyclable PCFC cathode material.

2. The preparation method according to claim 1, characterized in that: In the step (2), the molar amount of glycine is 2-3 times of the total molar amount of metal ions, and the molar amount of citric acid is 1.5-2 times of the total molar amount of metal ions.

3. A method for recycling recyclable PCFC cathode materials, characterized in that: The steps include: (1) The recyclable PCFC cathode material Ba as claimed in claim 1 1.1 (Gd 0.8 La 0.2 ) 0.9 (Co 1.5 Fe 0.5 ) 6-δ Manually dismantle the waste batteries to obtain waste cathode materials; (2) The waste cathode material was crushed in an agate mortar and ball-milled at 400 rpm for 3-5 h, and a 0.5-1.0 mol / L dilute nitric acid solution was prepared. The weight ratio of concentrated nitric acid to powder was 3-5 wt%, and the cathode powder was added to the dilute nitric acid solution for washing to obtain cathode powder A; (3) The cathode powder A obtained in step (2) was ball-milled at 400 rpm for 3-5 h, and then sintered at 1100 °C for 3-5 h to obtain cathode powder B; (4) The cathode powder B obtained in step (3) was ball-milled at 400 rpm for 2 h to obtain regenerated cathode powder C.

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