“田忌賽馬”是我國戰(zhàn)國時期的著名成語典故,流傳至今,影響深遠(yuǎn)。當(dāng)時齊國流行賽馬,大將田忌經(jīng)常輸給齊威王。一日,好友孫臏建議讓田忌的上、中、下馬分別對戰(zhàn)齊威王的中、下、上馬。不出所料,田忌以兩勝一負(fù)的成績最終贏得比賽。即“今以君之下駟與彼上駟,取君上駟與彼中駟,取君中駟與彼下駟。而田忌一不勝而再勝,卒得王千金”。其核心邏輯可解釋為以犧牲下等馬為代價從而取得另外兩場比賽的勝利,也即通過犧牲次要因素來實(shí)現(xiàn)主要目標(biāo)。
圖1 受“田忌賽馬”典故啟發(fā),以犧牲電滯回線負(fù)向鐵電性為代價來提升其正向儲能密度
鐵電材料的電滯回線是以原點(diǎn)對稱的曲線,而電介質(zhì)儲能在實(shí)際應(yīng)用往往只考慮其第一象限,即外加電壓一般為正向的三角波或正弦波,此時電滯回線的第三象限實(shí)則無用。受“田忌賽馬”典故的啟發(fā),若能以犧牲第三象限這個次要因素來進(jìn)一步提升第一象限的擊穿場強(qiáng)(Eb)或最大極化強(qiáng)度(Pmax),則可從一個額外的自由度提高鐵電材料的儲能密度。在半導(dǎo)體理論中,金屬-n型半導(dǎo)體接觸(metal-n-type semiconductor contact)往往會由于在界面處形成肖特基接觸而使其I-V特性曲線出現(xiàn)不對稱現(xiàn)象,即整流現(xiàn)象?;诖?,在鐵電氧化物薄膜的生長過程中,若在電極附近誘導(dǎo)出合適的氧空位,則可在理論上使薄膜擁有“鐵電半導(dǎo)”行為,即同時呈現(xiàn)電滯回線的滯回性與I-V特性曲線的整流性。電智學(xué)院孫梓雄博士憑借前期對鐵電憶阻器的研究基礎(chǔ),經(jīng)過對氧壓與薄膜厚度的多尺度調(diào)控,以生長次序與生長周期為雙變量,利用脈沖激光沉積(PLD)技術(shù)生長出由常規(guī)BCZT層與缺氧型BCZT層組成的多層薄膜。發(fā)現(xiàn)當(dāng)以缺氧型BCZT為起始層的單周期薄膜具有最高擊穿場強(qiáng)與最佳儲能特性。經(jīng)分析,該結(jié)果是由于底電極與薄膜界面處形成的肖特基勢壘重新優(yōu)化了多層薄膜的分壓,以犧牲薄膜負(fù)向鐵電性為代價提高了薄膜正向的擊穿場強(qiáng)。
圖2 不同結(jié)構(gòu)薄膜在正向三角波下的電滯回線與BCZT/BCZT-OD//(1P)薄膜/電極界面附近在正偏壓下的能帶結(jié)構(gòu)
電介質(zhì)儲能的常規(guī)研究策略主要集中在界面工程(Interface Engineering)與電疇工程(Domain Engineering)等,即電介質(zhì)本身,本研究則聚焦與優(yōu)化電介質(zhì)與電極之間的相互作用,為高性能電容器的設(shè)計與研發(fā)提供了思路。該項工作受到國家自然科學(xué)基金面上項目、青年科學(xué)基金項目,國家留學(xué)基金委博士后項目等項目的資助。全文鏈接:https://pubs.rsc.org/en/content/articlelanding/2025/mh/d4mh01651c。
新聞小貼士:
孫梓雄博士長期從事電子信息功能材料與器件及其智能化的相關(guān)研究,近年來發(fā)表多篇高水平論文:
1. Zixiong Sun*, Haoyang Xin, Liming Diwu, Zhanhua Wang*, Ye Tian, Hongmei Jing*, Xiuli Wang, Wanbiao Hu, Yongming Hu, Zhuo Wang*, Boosting the energy storage performance of BCZT-based capacitors by constructing the Schottky contact, Mater. Horiz. 2025, DOI: 10.1039/D4MH01651C.
2. Zixiong Sun*, Yuhan Bai, Hongmei Jing*, Tianyi Hu, Kang Du, Qing Guo, Pan Gao, Ye Tian, Chunrui Ma, Ming Liu*, Yongping Pu*, A Polarization double-enhancement strategy to achieve super low energy consumption with ultra-high energy storage capacity in BCZT-based relaxor ferroelectrics, Mater. Horiz. 2024, 11, 3330-3344.
3. Zixiong Sun*, Hansong Wei, Shibo Zhao, Qing Guo, Yuhan Bai, Siting Wang, Peiyao Sun, Kang Du, Yating Ning, Ye Tian, Xiaohua Zhang, Hongmei Jing, Yongping Pu, Sufeng Zhang*, Utilizing the synergistic effect between the Schottky barrier and field redistribution to achieve high-density, low-consumption, cellulose-based flexible dielectric films for next-generation green energy storage capacitors, J Mater. Chem. A, 2024, 12, 128-143.
4. Zixiong Sun*, Jiaqi Liu, Hansong Wei, Qing Guo, Yuhan Bai, Shibo Zhao, Siting Wang, Lei Li, Yutao Zhang, Ye Tian, Xiaohua Zhang, Hongmei Jing, Yongping Pu, Sufeng Zhang*, Ultrahigh energy storage capacity in multilayer-structured cellulose-based dielectric capacitors caused by interfacial polarization-coupled Schottky barrier height, J Mater. Chem. A, 2023, 11, 20089-20101.
5. Zixiong Sun*, Shibo Zhao, Ting Wang, Hongmei Jing*, Qing Guo, Ruyue Gao, Liming Diwu, Yongming Hu*, Yongping Pu*, Achieving high overall energy storage performance of KNN-based transparent ceramics by ingenious multiscale designing, J Mater. Chem. A, 2024, 12, 16735-16747.
(核稿:雷濤 編輯:劉倩)