活性炭的電化學性能

　　能(neng)(neng)源(yuan)(yuan)問(wen)題是21世(shi)紀活性炭電化(hua)學(xue)性能(neng)(neng)*顯著的(de)(de)(de)全(quan)球(qiu)挑戰之一(yi)。全(quan)球(qiu)對能(neng)(neng)源(yuan)(yuan)供應(ying)和環(huan)境保護的(de)(de)(de)需(xu)(xu)求(qiu)急劇增(zeng)加，迫使世(shi)界(jie)面臨經(jing)濟危機。據*近(jin)報道，全(quan)球(qiu)能(neng)(neng)耗每年(nian)約為4.1×10 20 J--其80%來自不(bu)(bu)可(ke)再生(sheng)碳(tan)密集型(xing)化(hua)石(shi)(shi)燃(ran)料(liao)，包括煤、石(shi)(shi)油和天(tian)然氣。過度依(yi)賴燃(ran)燒化(hua)石(shi)(shi)燃(ran)料(liao)帶來了許(xu)多環(huan)境問(wen)題，增(zeng)加了全(quan)球(qiu)經(jing)濟的(de)(de)(de)負(fu)擔(dan)。隨著世(shi)界(jie)的(de)(de)(de)不(bu)(bu)斷發展，能(neng)(neng)源(yuan)(yuan)需(xu)(xu)求(qiu)迅速增(zeng)長(chang)，地球(qiu)不(bu)(bu)可(ke)再生(sheng)能(neng)(neng)源(yuan)(yuan)總量相(xiang)當有限。因此，為了滿足日益(yi)增(zeng)長(chang)的(de)(de)(de)能(neng)(neng)源(yuan)(yuan)需(xu)(xu)求(qiu)，減少(shao)對環(huan)境的(de)(de)(de)應(ying)力，需(xu)(xu)要(yao)安(an)全(quan)、實用、可(ke)持續(xu)、性能(neng)(neng)良好的(de)(de)(de)能(neng)(neng)量轉換(huan)和存儲設備。

　　電(dian)(dian)化學電(dian)(dian)容器*近引起了人們的(de)(de)極大興趣，包括顯著的(de)(de)循環(huan)效率(lv)、預期(qi)的(de)(de)循環(huan)壽(shou)命、快(kuai)速充放電(dian)(dian)率(lv)和(he)(he)優良的(de)(de)功(gong)率(lv)密度，以(yi)及便攜式電(dian)(dian)子、混(hun)合電(dian)(dian)動汽車和(he)(he)存儲器的(de)(de)備用設備。毫(hao)無疑問，活(huo)(huo)性(xing)炭(tan)雙層電(dian)(dian)容器的(de)(de)性(xing)能主要取決于其電(dian)(dian)極材料的(de)(de)類型和(he)(he)形式。超級電(dian)(dian)容器的(de)(de)紋理電(dian)(dian)位電(dian)(dian)極材料研究以(yi)各(ge)種形式進行了報(bao)道(dao)。以(yi)活(huo)(huo)性(xing)炭(tan)為材料，如活(huo)(huo)性(xing)炭(tan)、石墨(mo)烯、碳(tan)納米(mi)結構，如管道(dao)和(he)(he)纖維、來(lai)自(zi)碳(tan)化物的(de)(de)碳(tan)等。

　　此外(wai)，活性(xing)(xing)炭具有多孔結(jie)構豐富(fu)、雜原子自摻(chan)雜、物(wu)理化(hua)學穩定(ding)性(xing)(xing)和環保等優點，廣泛(fan)應(ying)用于能(neng)源(yuan)相關領域，以滿足能(neng)源(yuan)供應(ying)的(de)迫切(qie)需求。截至目前(qian)(qian)，堅果(guo)殼、椰殼、木材、動物(wu)骨、纖(xian)維等各種活性(xing)(xing)炭材料已被廣泛(fan)用作(zuo)制造電(dian)容器的(de)前(qian)(qian)體。大(da)多數(shu)報告稱，活性(xing)(xing)炭的(de)儲(chu)能(neng)性(xing)(xing)能(neng)超過了其他非活性(xing)(xing)炭材料的(de)儲(chu)能(neng)性(xing)(xing)能(neng)。

　　活性炭的電化學性能

　　5%的(de)電(dian)(dian)(dian)(dian)極(ji)PTFE，乙炔碳黑10%，活性(xing)炭85%。將所(suo)有材料均勻混(hun)合(he)，然后在(zai)(zai)1.4MPa將其壓(ya)在(zai)(zai)鎳(nie)泡沫基材上，然后在(zai)(zai)真空烘箱(xiang)中(zhong)壓(ya)在(zai)(zai)110℃干(gan)燥12小時。每個集(ji)電(dian)(dian)(dian)(dian)器(qi)上的(de)活性(xing)物質量(liang)約為4.7mg·cm -2。6.通過多(duo)孔膜分離M KOH對稱雙電(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)池(chi)組(zu)裝電(dian)(dian)(dian)(dian)解質水溶液。采用循環伏安法(CV)，恒電(dian)(dian)(dian)(dian)流充放電(dian)(dian)(dian)(dian)(GCD)電(dian)(dian)(dian)(dian)化學阻抗光譜(EIS)研(yan)究(jiu)樣(yang)品(pin)的(de)電(dian)(dian)(dian)(dian)容性(xing)能。在(zai)(zai)0.01Hz-100KHz在(zai)(zai)5的(de)頻率范圍內mV在(zai)(zai)開路電(dian)(dian)(dian)(dian)位下測量(liang)范圍EIS光譜。所(suo)有電(dian)(dian)(dian)(dian)化學測量(liang)均在(zai)(zai)電(dian)(dian)(dian)(dian)化學工(gong)作站進行。所(suo)有試驗均在(zai)(zai)室(shi)溫下進行。

　　活性炭的(de)形狀和結(jie)構

　　四個活(huo)性(xing)炭(tan)樣(yang)(yang)品(pin)(pin)(LSC-1-4)的XRD圖譜顯(xian)示沒有(you)尖銳(rui)和強峰(feng)(如圖1所示)，表(biao)示所有(you)活(huo)性(xing)炭(tan)樣(yang)(yang)品(pin)(pin)的非晶狀態。一(yi)方面位于23左右(you)°位于44的寬(kuan)峰(feng)和寬(kuan)峰(feng)°弱峰(feng)是(shi)無(wu)定形石(shi)墨(mo)碳的特征峰(feng)，表(biao)明(ming)(ming)LSC樣(yang)(yang)品(pin)(pin)的石(shi)墨(mo)化(hua)程(cheng)度有(you)限。另一(yi)方面，以44°中(zhong)心弱峰(feng)的出現表(biao)明(ming)(ming)電導率的提(ti)(ti)高(gao)。特別地，LSC-1在44°與其他(ta)樣(yang)(yang)品(pin)(pin)相比，觀察到的尖銳(rui)峰(feng)值表(biao)明(ming)(ming)，LSC-石(shi)墨(mo)化(hua)程(cheng)度提(ti)(ti)高(gao)。

　　電(dian)化學表(biao)征活性炭

　　基(ji)于(yu)活(huo)性炭(tan)(tan)的(de)超(chao)級(ji)(ji)電(dian)(dian)(dian)(dian)容(rong)(rong)器的(de)活(huo)性炭(tan)(tan)樣品(SC-LSC)的(de)電(dian)(dian)(dian)(dian)容(rong)(rong)性，LSC-3和LSC-4通(tong)過電(dian)(dian)(dian)(dian)化(hua)學技術序列進行評估，包括室溫下(xia)CV，GCD和EIS測試。圖2顯(xian)(xian)示了四個不同掃描(miao)速(su)率的(de)人SC-LSC的(de)CV電(dian)(dian)(dian)(dian)勢窗的(de)范圍為0-0.8V。如(ru)所見，所有(you)超(chao)級(ji)(ji)電(dian)(dian)(dian)(dian)容(rong)(rong)活(huo)性炭(tan)(tan)在(zai)(zai)(zai)(zai)相對較低的(de)掃描(miao)速(su)率下(xia)具有(you)理想的(de)矩形(xing)電(dian)(dian)(dian)(dian)容(rong)(rong)性能(neng)，即充電(dian)(dian)(dian)(dian) - 雙層(ceng)(ceng)電(dian)(dian)(dian)(dian)容(rong)(rong)器在(zai)(zai)(zai)(zai)放電(dian)(dian)(dian)(dian)過程中的(de)典型性質(zhi)。即使在(zai)(zai)(zai)(zai)500 mV·s -在(zai)(zai)(zai)(zai)1的(de)高(gao)掃描(miao)速(su)率下(xia)，如(ru)圖2所示d，SC-LSCs的(de)CV由于(yu)樣品的(de)優良導電(dian)(dian)(dian)(dian)性和低質(zhi)量傳輸電(dian)(dian)(dian)(dian)阻，曲線保持(chi)了伏安曲線的(de)準(zhun)矩形(xing)狀，幾乎沒有(you)變(bian)形(xing)。顯(xian)(xian)然，短離(li)子通(tong)道和電(dian)(dian)(dian)(dian)解質(zhi)儲層(ceng)(ceng)的(de)快速(su)離(li)子運輸來自活(huo)性炭(tan)(tan)樣品的(de)分層(ceng)(ceng)孔(kong)結構。類似(si)地，超(chao)級(ji)(ji)電(dian)(dian)(dian)(dian)容(rong)(rong)活(huo)性炭(tan)(tan)由于(yu)理想的(de)分層(ceng)(ceng)多孔(kong)結構和活(huo)性炭(tan)(tan)的(de)高(gao)表面(mian)積而顯(xian)(xian)示出*高(gao)的(de)電(dian)(dian)(dian)(dian)容(rong)(rong)值。

　　碳化(hua)活(huo)化(hua)前，由纖(xian)維(wei)材料合成四種活(huo)性(xing)炭(tan)(tan)。所(suo)有(you)(you)制(zhi)(zhi)(zhi)備的(de)(de)活(huo)性(xing)炭(tan)(tan)主(zhu)要(yao)表(biao)現為微(wei)孔結構。發現通過ZnCl 2活(huo)化(hua)法制(zhi)(zhi)(zhi)備的(de)(de)活(huo)性(xing)炭(tan)(tan)表(biao)現出*大(da)的(de)(de)比表(biao)面(mian)積，在(zai)(zai)所(suo)有(you)(you)活(huo)性(xing)炭(tan)(tan)樣品中(zhong)表(biao)現出*佳的(de)(de)電(dian)(dian)化(hua)學(xue)(xue)性(xing)能(neng)，其中(zhong)0.1A·g 的(de)(de)電(dian)(dian)容(rong)(rong)(rong)為107.4F·g -1 -1.對稱雙電(dian)(dian)極電(dian)(dian)池。隨著電(dian)(dian)流密(mi)度大(da)于(yu)1，這些活(huo)性(xing)炭(tan)(tan)基超級(ji)(ji)(ji)電(dian)(dian)容(rong)(rong)(rong)器的(de)(de)電(dian)(dian)容(rong)(rong)(rong)僅大(da)于(yu)1A·g -而略(lve)有(you)(you)變化(hua)。所(suo)有(you)(you)超級(ji)(ji)(ji)電(dian)(dian)容(rong)(rong)(rong)器在(zai)(zai)1中(zhong)顯(xian)示出優(you)異的(de)(de)電(dian)(dian)化(hua)學(xue)(xue)穩定性(xing)A·g -1的(de)(de) 充放(fang)電(dian)(dian)循環5000次后，LSC-1型超級(ji)(ji)(ji)電(dian)(dian)容(rong)(rong)(rong)器的(de)(de)電(dian)(dian)容(rong)(rong)(rong)保持在(zai)(zai)92.6%以上。這些結果表(biao)明(ming)，纖(xian)維(wei)材料是合理(li)設計(ji)和制(zhi)(zhi)(zhi)備具有(you)(you)高表(biao)面(mian)積和優(you)良電(dian)(dian)化(hua)學(xue)(xue)性(xing)能(neng)的(de)(de)活(huo)性(xing)炭(tan)(tan)的(de)(de)好(hao)候選人。