과학/물리학

산화-환원 흐름 전지, Redox flow battery, 알카라인 충전지, Alkaline rechargeable battery

bjiu 2025. 1. 25. 00:53

[산화-환원 흐름 전지]
영어로는 Redox flow battery. 산화-환원 반응이 일어나는 전해질이 액체 상태로 흐르기 때문에 이런 이름이 붙었다. 이온교환막으로 분리된 두 액체 전해질을 이용하는 방식이다. 원리는 산화수가 다른 두 금속 이온끼리 산화-환원 반응이 일어나며 전극을 타고 전자가 이동하는 것이다. 이때 핵심은 반응물과 생성물이 모두 금속이온이라는 점이다. 즉, 사용한 이온들은 흘려보내고, 새로운 이온을 투입시키면 계속 전기가 발생하는 것이다. 기존의 배터리는 저장용량을 키우는 것에 한계가 있었지만, 흐름전지는 단순히 전해질을 보관할 탱크만 더 지으면 간단하게 용량이 늘어나게 되며, 앙금이 생성되지 않아 전극의 변형도 적게 일어나므로 대용량 축전지로 활발하게 연구중이다.

유명한 흐름전지로는 산화수가 다른 두 바나듐 이온을 이용한 전지(바나듐 레독스 흐름 전지)가 있으며, 그밖에 아연||세륨 흐름전지도 활발히 연구중이다.


[알카라인 충전지]
보통 알카라인 전지는 충전이 불가능한 일차 전지이며 충전을 시도할 경우 가스가 발생해 누액으로 이어질 수 있다. 그러나 이를 억제해 충전이 가능하게 만든 알카라인 전지도 존재한다. 하지만 충방전 사이클 수명이 최대 100회 내외로 짧은 편이며, 리튬 이온은 물론이고 니켈 계열 전지보다도 성능이 떨어지므로 거의 판매되지 않는다. 그러나 월간 방전률이 1%로 니켈 수소 전지보다 낮으며, 평균 전압이 1.2V가 아닌 1.5V이므로 리모컨처럼 전력 소비가 낮은 부하나 반드시 1.5V를 요하는 기기에 적합하다.

 

 

 

[Redox flow battery]
Redox flow battery in English. It got its name because the electrolyte in which the oxidation-reduction reaction occurs flows in a liquid state. It uses two liquid electrolytes separated by an ion exchange membrane. The principle is that two metal ions having different oxidation numbers undergo an oxidation-reduction reaction, and electrons move through the electrode. The key at this time is that both the reactant and the product are metal ions. In other words, the used ions are allowed to flow away, and electricity is continuously generated when new ions are added. Existing batteries had limitations in increasing storage capacity, but flow batteries simply increase capacity by building more tanks to store electrolytes, and since charge is not generated, deformation of the electrode occurs less, so they are actively being studied as large-capacity storage batteries.

Famous flow batteries include batteries using two vanadium ions with different oxidation numbers (vanadium redox flow batteries), and zinc||cerium flow batteries are also being actively studied.


[Alkaline rechargeable batteries]
Alkaline batteries are typically primary batteries that cannot be charged, and when charging is attempted, gas is generated, which can lead to leakage. However, there are alkaline batteries that suppress this and enable charging. However, it is rarely sold because the charge/discharge cycle life is short, up to 100 times, and its performance is lower than that of nickel-based batteries as well as lithium ions. However, because the monthly discharge rate is 1% lower than that of nickel-hydrogen batteries, and the average voltage is 1.5V rather than 1.2V, it is suitable for low-power loads like remote controls or devices that must require 1.5V.