



摘""要:"有機分子具有結構可設計、理論比容量高的優點,在鋰離子電池負極材料領域具有潛在的應用價值,但由于其具有易溶解和循環穩定性差等缺點,電池性能表現不佳. 有機分子中六苯并蔻(HBC)具有高穩定性,而1,4-苯醌(BQ)具有高比容量,選擇把這兩種分子復合作為新的有機負極材料,并對其在鋰離子電池中的表現進行了全面的對比測試. 結果表明:復合后的材料兼具HBC的穩定性與BQ的高比容量,并且有清晰的充放電平臺,尤其是以物質的量之比為1∶6復合的材料,在200 mA·g-1的電流密度下循環300圈后,仍保持330.9 mAh·g-1的比容量,庫倫效率高達99.51%. 此研究為有機負極材料的設計與應用提供了新思路.
關鍵詞:"六苯并蔻(HBC);"有機負極材料;"鋰離子電池;"新型能源材料
中圖分類號:"O 625.15 """文獻標志碼:"A """文章編號:"1000-5137(2025)01-0036-07
Cycling performance of hexabenzocoronene-based anode materials for lithium-ion batteries
WANG Xinqian,"YANG Lei,"ZHU Xin,"XU Jingjing*,"XIAO Shengxiong*
(College of Chemistry and Materials Science,"Shanghai Normal University,"Shanghai 200234,"China)
Abstract:"Organic molecules have the advantages of designable structure and high theoretical specific capacity,"which have potential applications in the field of anode materials for lithium-ion batteries,"but they perform poorly due to their ease of dissolution and poor cycling stability. As organic molecules,"hexabenzocoronene(HBC)"has superior stability and 1,4-benzoquinone (BQ)"has high specific capacity. We chose to combine these two molecules as a new organic anode material,"and carried out a comprehensive comparative test on its performance in lithium-ion batteries. The results show that the composite material combines the stability of HBC with the high specific capacity of BQ and has a clear charging/discharging platform. Especially,"the composite material with a molar ratio of 1∶6 maintains a specific capacity of 330.9 mAh·g-1"with a Coulombic efficiency as high as 99.51% after cycling for 300 cycles at a current density of 200 mA·g-1. This study provides a new insight for the design and application of organic anode materials.
Key words:"contorted hexabenzocoronene (HBC);"organic anode material;"lithium-ion batteries;"novel energy materials
0 "引"言
隨著電動汽車與消費電子產品的快速發展,人們對高能量密度存儲體系的需求日益增長[1]. 然而,大多數傳統商用電極材料仍面臨著資源稀缺[2]、成本高昂[3]和環境問題[4]等嚴峻挑戰. 此外,有限的理論比容量也嚴重阻礙了它們的進一步發展[5].
與此相反,有機材料因其具備材料資源豐富、結構多樣和生態友好可持續發展等優點,成為前景廣闊的電極材料[6]. 作為電極材料,有機小分子具有理論比容量高[7]、合成條件溫和[8]、分子結構可設計[9]等多種優勢,其分子結構的可設計性使之具有豐富的官能團及氧化還原活性中心,從而展現優良的電化學性能. 但有機材料存在密度低、電子傳導性差、穩定性差,以及易溶于液體電解質等問題"[10],導致電池容量快速衰減,嚴重限制了它們在鋰離子電池中的電化學性能[11]. 目前,人們大多采取聚合[12-13]、金屬有機框架(MOFs)[14-16]、共價有機框架(COFs)[17-19]"和氫鍵有機框架(HOFs)[20-21]"等方法抑制有機小分子的溶解,但是除了合成方法復雜和活性位點密度低之外,這些方法還會不可避免地引入非氧化還原活性單元[22],從而降低電極材料的比容量.
2018年,PARK等"[23]用非平面稠環芳香烴扭曲六苯并蔻(HBC)作為鋰電池的負極材料,其分子層間空隙中可吸附鋰離子,從而顯示出了較高的容量以及循環穩定性. 隨后,PARK等[24]又將HBC與富勒烯(C60)復合形成了一種有機共晶體,為鋰離子提供了插層空位,并增強了其電子傳輸,從而得到了相較于單種材料更高的可逆容量. 然而,該課題組沒有進行更進一步的研究,而C60價格昂貴也不利于材料的實際應用. 本文選用更廉價易得的吸電子有機小分子1,4-苯醌(BQ)替代C60,與HBC復合得到了新的負極材料.
選用BQ是因為其所屬的羰基化合物理論容量高(通常大于200 mAh·g-1)、可逆性好和氧化還原速率快[25]. 用BQ和HBC復合以期結合兩者的優勢改善小分子作為電池電極材料易溶解、穩定性差的缺點. 按物質的量之比1∶1和1∶6的配比組裝的紐扣電池,其電化學以及循環測試結果表明,復合的電極材料兼具了HBC的穩定性和BQ的高比容量,為今后有機電極材料的設計提供了新的思路.
1 "實驗部分
1.1 實驗試劑
鄰苯二甲醛(OPA)、1,4-環己二酮(C6H8O2)、三苯基膦(PPh3)、四溴化碳(CBr4)、苯硼酸(PBA)、二氯甲烷(DCM)、甲苯(PhMe)、無水乙醇(EtOH)、甲醇(MeOH)、石油醚(PE)、四(三苯基)膦鈀(Pd(PPh3)4)、環氧丙烷(PO)和碘單質(I2)購自Adamas公司;氯化鉀(KCl)、氫氧化鈉(NaOH)、碳酸鈉"(Na2CO3)、無水硫酸鈉(Na2SO4)購自Greagent公司;金屬鋰片、導電炭黑、305電解液和隔膜購自Titan公司;所用銅箔購自深圳市科晶智達科技有限公司.
1.2 實驗儀器
電化學工作站,CHI760E;藍電電池測試系統,LANDdt;真空干燥箱,DZF-6050A;氬氣手套箱,UNILAB2000Bruker Tensor 27.
1.3 合成步驟
根據已有文獻的步驟合成了HBC分子,其合成路線如圖1所示[26].
1.3.1 化合物1的合成
取24 g OPA和10 g C6H8O2溶解在500 mL EtOH中,緩慢滴入飽和NaOH溶液,直至有沉淀生成,加快攪拌速率,有大量黃色沉淀產生時,停止滴加,升溫至75 ℃,反應12 h. 反應結束后,過濾,用水和EtOH洗滌至濾液無色透明,得到22.5 g黃色固體產物1,產率為81%.
1.3.2 化合物2的制備
在氮氣(N2)氛圍下,取85 g PPh3溶解在500 mL PhMe中,30 min 后加入54 g CBr4"反應,"繼續通氣30 min,反應體系變為黃色,再加入化合物110 g,最后通氣15 min后,升溫至110 ℃反應過夜. 反應結束后降至室溫,將反應液中"PhMe旋干后,用DCM/MeOH重結晶得到14.1 g白色固體化合物2,產率為70%.
1.3.3 化合物3的合成
稱取1 g化合物2、1.18 g PBA、2.74 g Na2CO3于150 mL厚壁耐壓瓶中,然后加入60 mL PhMe和20 mL水,通N2"20 min 除掉氧氣"(O2),加入372.78 mg Pd(PPh3)4,升溫至90 ℃反應24 h. 反應結束后,冷卻至室溫,DCM萃取3次,用Na2SO4干燥,旋干溶劑. 以體積比V(DCM)∶V(PE)=3∶1 為洗脫劑,采用柱層析法分離得到670 mg白色固體化合物3,產率為68%.
1.3.4 化合物4的制備
稱取500 mg化合物3溶解于250 mL無水PhMe中,通N2"30 min除去O2后,加入1 g I2和5 mL PO,N2氣氛下用紫外燈照射12 h,反應結束后,將反應液過濾,用MeOH洗滌,得到320 mg黃色固體化合物4(HBC),產率為65%. 經對比,化合物4核磁結果與文獻中結果一致[26].
1.3.5 HBC@BQ復合物的制備
分別按物質的量之比為1∶1和1∶6分別稱取HBC與BQ,將其完全溶解后旋干除去溶劑,干燥后得到HBC@BQ(1∶1)和HBC@BQ(1∶6)兩種材料.
2 "結果與討論
2.1 電化學測試
為了初步確定混合材料的電化學性能,判斷復合后的材料是否適合用作鋰電池負極,對分別用4種材料作為負極的鋰電池進行了交流阻抗譜測試以及循環伏安掃描測試.
圖2顯示了HBC,BQ,HBC@BQ(1∶1)和HBC@BQ(1∶6)分別用作鋰電池負極材料時,通過電化學工作站在頻率為0.01~100 000 Hz、交流電(AC)振幅為"10 mV的范圍內測試的交流阻抗圖譜. 如圖2所示,HBC和BQ兩種材料阻抗分別達到了854 Ω和1 820 Ω,而復合后的材料HBC@BQ(1∶1)和HBC@BQ(1∶6)阻抗僅有580 Ω和220 Ω,遠小于復合前的材料,表明復合后的材料有更好的離子導電性,同時,由此預測復合后的材料比未處理的材料具有更高的循環容量.
循環伏安掃描設置了0.5 mV·s-1的掃速和0.1~3.0 V的電勢范圍,結果如圖3所示,這4種材料均在0.3~0.6 V范圍內有清晰的氧化峰,還原峰位置則接近0 V,這些數據表明了所選材料適合用做鋰電池負極. 與HBC和BQ兩種原材料相比,復合后的材料HBC@BQ(1∶1)和HBC@BQ(1∶6)氧化峰更高,且峰形更為尖銳,氧化峰面積更大,表明復合后的電極材料有更高的比容量. 其中,更加尖銳的峰形則表明新電極材料有更平穩的充放電平臺.
2.2 恒流充放電測試
對4種材料在不同電流密度下分別進行循環性能測試. 如圖4所示,在200 mA·g-1電流密度下,4種材料均在循環過程中比容量有所上升,這歸因于材料內部結構的緩慢活化. 其中HBC的循環曲線比較平穩,而BQ充放電過程波動相對較大,與HBC復合后,循環曲線比復合前平穩,說明兩者復合之后兩種材料發生了相互作用,使材料性能更好. 除穩定性有所改善之外,HBC@BQ(1∶1)和HBC@BQ(1∶6)的比容量明顯高于HBC本身,與BQ相比也有一定提升. 推測是HBC的存在提升了BQ的循環穩定性,同時BQ的存在撐開了HBC的儲鋰通道,提升了循環比容量.
2.3 倍率性能測試
最后,在不同電流密度下測試了4種材料的倍率性能. 如圖5所示,電流密度由0.1 A·g-1逐漸升至5 A·g-1,最后再恢復到0.1 A·g-1,電流密度上升時HBC的比容量分別為115,76,66,43,34,32和28 mAh·g-1,"當電流密度回到0.1 A·g-1后,電池比容量回到122 mAh·g-1. 另外,BQ的比容量分別為178,114,106,88,67,60,43和189 mAh·g-1;HBC@BQ(1∶1)的比容量分別為171,122,102,70,48,40,36和182 mAh·g-1;HBC@BQ (1∶6)的比容量分別為228,218,204,180,150,132,75和264 mAh·g-1. 在經歷不同電流大小的充放電后,4種材料均沒有比容量損失,顯示出良好的倍率性能. 其中,HBC@BQ(1∶6)在所有電流密度下的比容量都是最高的,而HBC@BQ(1∶1)在小電流密度下,也有更高的比容量,且大電流密度下比容量高于HBC,與BQ相差不大.
4種材料的充放電測試結果如圖6所示,HBC在0.3 V左右有一個放電平臺,與循環伏安掃描圖中的氧化峰位置相對應;而BQ的氧化峰為一個包峰,充放電曲線中也沒有明顯的放電平臺. 而復合材料HBC@BQ(1∶1)和HBC@BQ(1∶6)在氧化峰出峰位置有更為明顯的放電平臺,印證了推測,HBC提升了材料的循環穩定性,提供了放電平臺,與HBC和C60復合形成的共晶不同,BQ分子撐開了HBC間的分子層,拓寬了儲鋰通道,從而減小了材料的阻抗,提高了材料的鋰離子擴散系數,具有更清晰穩定的放電平臺,提高了材料的比容量.
3 "結"語
把具有給電子效應的非平面稠環芳香烴共軛體系HBC與具有吸電子效應的有機小分子BQ結合在一起,成功復合出了新的有機電極材料. 通過增大插層空隙和增加鋰離子插層位點,達到了降低有機小分子溶解度、提高材料在電池中的穩定性以及提高電池比容量的效果. 此研究為電池有機負極材料的設計提供了新的思路和參考價值.
參考文獻:
[1] ARMAND M,"TERASCON J M. Building better batteries [J]. Nature,"2008,451(7179):652-657.
[2] HE W,"GUO W,"WU H,"et al. Challenges and recent advances in high capacity Li-rich cathode materials for high energy density lithium-ion batteries [J]. Advanced Materials,"2021,33(50):2005937.
[3] GOODENOUGH J B,"How we made the Li-ion rechargeable battery [J]. Nature Electronics,"2018,1(3):204.
[4] ZHAO Q,"STALIN S,"ZHAO C Z,"et al. Designing solid-state electrolytes for safe energy-dense batteries [J]. Nature Reviews Materials,"2020,5(3):229-252.
[5] CHOI J W,"AURBACH D,"Promise and reality of post-lithium-ion batteries with high energy densities [J]. Nature Reviews Materials,"2016,1(13):16013.
[6] LYU H,"SUN X G,"DAI S. Organic cathode materials for lithium-ion batteries:"past,"present,"and future [J]. Advanced Energy and Sustainability Research,"2021,2(1):2000044.
[7] ESSER B,"DOLHEM F,"BECUWE M,"et al. A perspective on organic electrode materials and technologies for next generation batteries [J]. Journal of Power Sources,"2021,482:228814.
[8] PENG J,"WU D,"LU P,"et al. High-safety,"wide-temperature-range,"low-external-pressure and dendrite-free lithium battery with sulfide solid electrolyte [J]. Energy Storage Materials,"2023,54:430-439.
[9] PENG J,"WU D,"SONG F,"et al. High current density and long cycle life enabled by sulfide solid electrolyte and dendrite-free liquid lithium anode [J]. Advanced Functional Materials,"2022,32(2):2105776.
[10] LIANG Y,"ZHANG P,"CHEN J,"Function-oriented design of conjugated carbonyl compound electrodes for high energy lithium batteries [J]. Chemical Science,"2013,4(3):1330-1337.
[11] LI L,"ZUO Z,"WANG F,"et al. In situ coating graphdiyne for high-energy-density and stable organic cathodes [J]. Advanced Materials,"2020,32(14):2000140.
[12] WANG J,"LEE Y,"TEE K,"et al. A nanoporous sulfur-bridged hexaazatrinaphthylene framework as an organic cathode for lithium ion batteries with well-balanced electrochemical performance [J]. Chemical Communications,"2018,54(55):7681-7684.
[13] WANG X,"ZHOU Z,"LIN X,"et al. Nanostructured hexaazatrinaphthalene based polymers for advanced energy conversion and storage [J]. Chemical Engineering Journal,"2022,34(14):6378-6388.
[14] DONG H,"GAO H,"GENG J,"et al. Quinone-based conducting three-dimensional metal-organic framework as a cathode material for lithium-ion batteries [J]. The Journal of Physical Chemistry C,"2021,125(38):20814-20820.
[15] YE Z,"JIANG Y,"LI L,"et al. Rational design of MOF-based materials for next-generation rechargeable batteries [J]. Nano-Micro Letters,"2021,13(1):203.
[16] WANG Y F,"POLDORN P,"WONGNONGWA Y,"et al. Cobalt(II)-hexaazatriphenylene hexacarbonitrile coordination compounds based cathode materials with high capacity and long cycle stability [J]. Advanced Functional Materials,"2022,32(16):2111043.
[17] LUO Z,nbsp;LIU L,"NING J,"et al. A microporous covalent-organic framework with abundant accessible carbonyl groups for lithium‐ion batteries [J]. Angewandte Chemie :"International Edition,"2018,57(30):9443-9446.
[18] WU M M,"ZHAO Y,"SUN B Q,"et al. A 2D covalent organic framework as a high-performance cathode material for lithium-ion batteries [J]. Nano Energy,"2020,70:104498.
[19] ZHENG S,"SHI D,"YAN D,"et al. Orthoquinone-based covalent organic frameworks with ordered channel structures for ultrahigh performance aqueous zinc-organic batteries [J]. Angewandte Chemie :"International Edition,"2022,61(12):e202117511.
[20] LIU X,"YANG X,"WANG H,"et al. A robust redox-active hydrogen-bonded organic framework for rechargeable batteries [J]. Journal of Materials Chemistry A,"2022,10(4):1808-1814.
[21] WU Y,"WANG Y,"WEI F,"et al. Engineering cyano groups into hydrogen-bonded organic supramolecules with multi redox centers for high-performance Li-ion battery cathode [J]. Energy Storage Materials,"2023,63:102993.
[22] LUO Z,"LIU L,"NING J,"et al. A microporous covalent-organic framework with abundant accessible carbonyl groups for lithium‐ion batteries [J]. Angewandte Chemie :"International Edition,"2018,57(30):9443-9446.
[23] PARK J,"LEE C W,"PARK J H,"et al. Capacitive organic anode based on fluorinated‐contorted hexabenzocoronene:"applicable to lithium‐ion and sodium‐ion storage cells [J]. Advanced Science,"2018,5(12):1801365.
[24] PARK J,"LEE C W,"JOO S H,"et al. Contorted polycyclic aromatic hydrocarbon:"promising Li insertion organic anode [J]. Journal of Materials Chemistry A,"2018,6(26):12589-12597.
[25] LUO Z,"LIU L,"ZHAO Q,"et al. An insoluble benzoquinone-based organic cathode for use in rechargeable lithium-ion batteries [J]. Angewandte Chemie :"International Edition,"2017,56:12561.
[26] XIAO S X,"MYERS M,"MIAO Q,"et al. Molecular wires from contorted aromatic compounds [J]. Angewandte Chemie :"International Edition,"2005,44:7390-7394.
(責任編輯:郁慧,包震宇)
基金項目:"上海市自然科學基金(22ZR1445900);"國家自然科學基金青年基金(22305156);"國家自然科學基金面上項目(21772123);"上海綠色能源化工工程技術研究中心項目(18DZ2254200);"光化學能源材料學科創新引智基地項目(D18020);"上海市部分地方院校能力建設專項(21010503400)
作者簡介:"王心倩(1999—),"女,"碩士研究生,"主要從事有機光電材料等方面的研究. E-mail:"2499402198@qq.com
* 通信作者:"徐京京(1991—),"女,"副教授,"主要從事有機發光材料和有機光電材料等方面的研究. E-mail:jingjingxu@shnu.edu.cn;"肖勝雄(1977—),"男,"教授,"主要從事稠環芳香有機半導體材料的合成、器件構筑及性能方面的研究. E-mail:"xiaosx@shnu.edu.cn
引用格式:"王心倩,"楊磊,"朱欣,"等. 基于六苯并蔻的負極材料在鋰離子電池中的循環性能表現"[J]. 上海師范大學學報"(自然科學版中英文),"2025,54(1):36?42.
Citation format:"WANG X Q,"YANG L,"ZHU X,"et al. Cycling performance of hexabenzocoronene-based anode materials for lithium-ion batteries [J]. Journal of Shanghai Normal University (Natural Sciences),"2025,54(1):36?42.