JP-2026075629-A - A negative electrode for a zinc secondary battery, and a nickel-zinc secondary battery and its usage method.

Abstract

[Problem] To provide a negative electrode for a zinc secondary battery that can delay the decrease in battery capacity during trickle charging and extend the battery life. [Solution] A negative electrode used in a zinc secondary battery, comprising ZnO particles and metallic Zn particles in an amount of 55.0 to 65.0 parts by weight per 100 parts by weight of ZnO particles. [Selection Diagram] Figure 1

Inventors

• 谷本 稔
• 八木 毅
• 小栗 歩
• 石原 寛己

Assignees

• ＮＧＫ株式会社

Dates

Publication Date

20260511

Application Date

20230323

Claims (10)

1. The negative electrode used in a zinc secondary battery, ZnO particles and, A metal Zn particle in an amount of 55.0 to 65.0 parts by weight per 100 parts by weight of the ZnO particles, The negative electrode, including the negative electrode.
2. The negative electrode according to claim 1, wherein the content of the metallic Zn particles is 55.0 to 58.0 parts by weight per 100 parts by weight of the ZnO particles.
3. The negative electrode according to claim 1, further comprising a binder resin.
4. A positive electrode plate containing nickel hydroxide and/or nickel oxyhydroxide, A negative electrode plate according to any one of claims 1 to 3, A hydroxide ion conductive separator that separates the positive electrode plate and the negative electrode plate in a manner that allows hydroxide ions to conduct, Electrolyte and A battery case in which the positive electrode plate, the negative electrode plate, and the hydroxide ion conductive separator are housed vertically, A nickel-zinc rechargeable battery equipped with [specific features/features].
5. The nickel-zinc secondary battery according to claim 4, wherein the hydroxide ion conductive separator is an LDH separator containing layered double hydroxide (LDH) and/or an LDH-like compound.
6. The nickel-zinc secondary battery according to claim 5, wherein the LDH separator is composited with a porous substrate.
7. The nickel-zinc secondary battery according to claim 4, wherein the negative electrode plate is covered with the hydroxide ion conductive separator, and the outer periphery of the negative electrode plate, excluding its upper end, is hermetically sealed, thereby preventing oxygen generated on the positive electrode plate from reaching the negative electrode plate.
8. The nickel-zinc battery comprises stacked cells, and the stacked cells are Multiple positive electrode plates, A plurality of positive electrode tab leads extending from each end of the positive electrode plate, Multiple negative electrode plates, Multiple negative electrode tab leads extend from each end of the negative electrode plate at positions that do not overlap with the positive electrode tab leads, A plurality of hydroxide ion conductive separators that isolate the positive electrode plate and the negative electrode plate in a manner that allows hydroxide ions to conduct, The aforementioned electrolyte, The nickel-zinc secondary battery according to claim 4, comprising the positive electrode plate and the negative electrode plate being alternately stacked with the hydroxide ion conductive separator in between.
9. A method for using a nickel-zinc secondary battery, comprising performing trickle charging on the nickel-zinc secondary battery described in claim 4 to provide a charging capacity of 80-85% of the battery's installed capacity.
10. The method for using a nickel-zinc secondary battery according to claim 9, wherein the charging capacity is 80% of the installed capacity of the nickel-zinc secondary battery.

Description

This invention relates to a negative electrode for a zinc secondary battery, a nickel-zinc secondary battery, and a method for using the same. In nickel-zinc secondary batteries, ZnO particles and metallic Zn particles are commonly used in combination in the negative electrode. Patent Document 1 (Japanese Patent Application Publication No. 2021-57339) discloses a negative electrode for a zinc secondary battery, comprising a negative electrode active material containing Zn particles and ZnO particles, and a conductive additive containing solder. This document states that the amount of Zn particles in the negative electrode is preferably 1 to 50 parts by weight, when the ZnO particle content is 100 parts by weight. Patent Document 2 (WO2022/118625) discloses a negative electrode for a zinc secondary battery, comprising a negative electrode active material containing ZnO particles and Zn particles, and a nonionic water-absorbing polymer. This document discloses that the negative electrode was prepared by adding 5.7 parts by weight of metallic Zn powder, 1 part by weight of polytetrafluoroethylene (PTFE), and optionally a nonionic water-absorbing polymer or an ionic water-absorbing polymer to 100 parts by weight of ZnO powder. Incidentally, in zinc secondary batteries such as nickel-zinc secondary batteries and zinc-air secondary batteries, it is known that during charging, metallic zinc deposits in a dendrite-like manner from the negative electrode, penetrates the voids in the separator such as nonwoven fabric, and reaches the positive electrode, resulting in a short circuit. Such short circuits caused by zinc dendrites lead to a shortened charge-discharge life. To address this problem, batteries equipped with a layered double hydroxide (LDH) separator that selectively allows hydroxide ions to permeate while preventing the penetration of zinc dendrites have been proposed (see, for example, Patent Documents 1 and 2, and Patent Document 3 (WO2016/076047) and Patent Document 4 (WO2019/124270)). Furthermore, Patent Documents 5 (WO2019/069760) and 6 (WO2019/077953) propose a zinc secondary battery in which the entire negative electrode active material layer is covered or enclosed by a liquid-retaining member and an LDH separator, and the positive electrode active material layer is covered or enclosed by a liquid-retaining member. Nonwoven fabric is used as the liquid-retaining member. This configuration eliminates the need for complicated sealing and bonding between the LDH separator and the battery container, allowing for the extremely simple and highly productive manufacture of zinc secondary batteries (especially their stacked batteries) capable of preventing zinc dendrite extension. Furthermore, LDH-like compounds are known as hydroxides and/or oxides with a layered crystalline structure that are similar to LDH, although they cannot be called LDH. These compounds exhibit hydroxide ion conductivity characteristics so similar to LDH that they can be collectively referred to as hydroxide ion conductive layered compounds (see, for example, Patent Documents 1 and 2). Specifically, Patent Document 7 (WO2020/255856) discloses a hydroxide ion conductive separator comprising a porous substrate and a layered double hydroxide (LDH)-like compound that seals the pores of the porous substrate, wherein the LDH-like compound is a hydroxide and/or oxide with a layered crystalline structure containing Mg and at least one element selected from the group consisting of Ti, Y, and Al, including at least Ti. Furthermore, Patent Document 8 (WO2021/229916) discloses an LDH separator using an LDH-like compound comprising (i) Ti, Y, and optionally Al and/or Mg, and (ii) at least one additive element M selected from the group consisting of In, Bi, Ca, Sr, and Ba. In addition, Patent Document 9 (WO2021/229917) discloses an LDH separator comprising a mixture of an LDH-like compound and In(OH) 3 , wherein the LDH-like compound is a layered crystalline hydroxide and/or oxide comprising Mg, Ti, Y, and optionally Al and/or In. The separators disclosed in Patent Documents 7 to 9 are said to have superior alkali resistance and to be able to more effectively suppress short circuits caused by zinc dendrites compared to conventional LDH separators. Japanese Patent Publication No. 2021-57339WO2022/118625WO2016/076047WO2019/124270WO2019/069760WO2019/077953WO2020/255856WO2021/229916WO2021/229917 Nickel-zinc secondary batteries have applications beyond cycle use involving repeated charge and discharge, including backup power supply during power outages. In backup applications, maintaining the battery capacity near full charge is desirable to ensure the minimum guaranteed capacity. Therefore, as shown in Figure 1, trickle charging (1) is performed to compensate for the battery capacity loss due to self-discharge (2). Trickle charging allows the battery capacity to be constantly maintained near full charge. However, a problem exists: trickle charging redu