Science Focus ( Issue 008 ) - page 9

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References
參考資料
[1] Tang, J. and Pol, V.G. From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room – and Elevated-
Temperature Li-ion Storage (2016). DOI: 10.1038/srep20290.
[2] Campbell, B. et al. Bio-Derived, Binderless, Hierarchically Porous Carbon Anodes for Li-ion Batteries (2015). DOI: 10.1038/srep14575.
[3] Wu, L., Buchholz, D., Vaalma, C., Guinevere, A. G., Passerini, S. Apple-Biowaste-Derived Hard Carbon as a Powerful Anode Material for
Na-Ion Batteries (2015). DOI: 10.1002/celc.201500437.
can be activated after numerous charges, future
electronics may see an increase, as opposed to a
decrease, in energy capacity.
As an alternative to lithium- ion batter ies,
German scientists are investigating sodium-ion
batteries with bio-waste-derived hard carbon
as the anode [3]. Sodium-ion batteries allow for
stationary energy storage, and are attractive to
scientists and investors because of its abundance,
great accessibility, and low cost. Organic waste
(which is carbon-based), such as apple cores, has
the application of anodes in sodium-ion batteries.
The cathode consists of multiple layers of sodium
oxides, which replace cobalt in conventional
lithium- ion batter ies. While, both sodium- ion
and lithium- ion batter y cathodes are similar
in efficiency, the former offers an eco-friendly
method of har vesting biomass and recycling
agricultural wastage.
An unprecedented increase in the demand
of energy storage for electronics is cur rently
exhausting our natural resources. Innovative
ideas that incorporate recyclability and the use
of naturally available resources to create these
technologies mark a great leap towards the
development of inexpensive and eco-friendly
batteries. The science exists, but the next step
is to commercialise these technologies in real-
life applications by cutting costs and enhancing
efficiency as well as power output.
池是由浸在電解質溶液中的正極和負極組成。在
常用的鋰離子電池中,鋰離子在充電時移向負極。現今多數
鋰離子電池的負極是由具有強導電性的石墨碳材製成。近
年,由於石墨的提純成本提高,石墨片產量下降,加上商品
稅率提高,導致石墨負極的生產成本大幅飆升。
石墨的超強導電性源於其結構,層層的遊離電子可以像
金屬電子般移動及導電。有見於市場對電子產品用電池的
需求將會激增,各方正嘗試開發導電性可與石墨電極比美的
替代品。工程師和科學家看中花粉和蘑菇等生物原料的多
樣而獨特的微結構,正在探索如何利用生物質中的碳微體
系結構來生產負極材料。
他們發現從蜂花粉和蒲黃花粉取得的硬碳結構有可能
製成儲能負極材料[1]。花粉經氬氣高溫處理後,熱解形成
多孔碳結構。研究顯示這些獨特微結構(樣品含大量氧氣)
的孔隙率,讓能量存儲量達到頂點,因此這種清潔可再生能
源技術可以應用於開發負極材料。
另一方面,加州大學河濱分校的工程師們利用褐菇帽的
皮製成另一類負極材料[2]。褐菇帽皮加熱後形成類似碳納
米帶的結構,有大量小孔讓液體或氣體通過,亦會提供空間
儲存和轉移能量。這些微孔是提高電池性能的關鍵。通過
類似花粉處理的過程,褐菇帽皮組織也可以熱解成為所需
的碳形態。碳架構中更有許多孔隙會隨著充電次數增加而
被啟動,未來電子產品經長期使用後,電容量可能是增加而
非減少。
德國科學家正在研究以鈉離子電池,配上從生物垃圾
衍生的硬碳所製成的負極材料,作為鋰離子電池的替代品
[3]。鈉離子電池可以成為固定儲能設備,而且優點眾多,
如:原料供應充足、提取容易、成本低,所以吸引不少科學家
和投資者青睞。有機廢物(碳基)如蘋果核,可以用作鈉離
子電池的負極。正極則由多層鈉氧化物組成,取代傳統鋰離
子電池所用的鈷。雖然兩者的效能不相伯仲,鈉離子電池可
以額外提供回收生物質和循環再用農業廢料的環保途徑。
電子產品所衍生的儲能需求空前增加,消耗我們的自然
資源。以上所介紹的種種方案,既有融入循環概念的創新思
路,亦有運用自然可得資源的新技術,標示著在廉價環保電
池的研發方面,已取得飛躍進展。下一步就要考慮削減成本
和提高效率,以及提高輸出功率,務求將這些技術商化應用
於現實生活中。
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