进入21世纪，人们对能源需求不断增长，走可持续发展道路和大力发展绿色能源产业成为一个具有挑战且不可避免的世界性课题。作为解决能源问题的重要途径，锂离子电池和钠离子电池在大规模的能源供应上却有很大局限性。电极材料是制约锂离子和钠离子电池发展的一大关键因素，因此寻找理想的高能量密度和高功率密度的电极材料具有重大意义。其中，锰氧化物由于自然资源丰富且理论容量高，作为锂离子电池电极材料有很好的应用前景。同时，探究锰氧化物作为钠离子电池电极材料的应用，也具有非常重要的科学意义。然而，锰氧化物作为电池电极材料仍然存在许多问题。一方面由于锰氧化物较低的电子电导和离子电导所造成的，另一方面是基于转换反应机制的锰氧化物，充放电中大的体积膨胀导致其循环性能差。本文采用纳米化以及预锂化策略对其进行优化。

本论文以锰氧化物为研究对象，设计构筑了MnO₂纳米线和纳米棒，并通过将MnO₂纳米线进行预锂化得到富锂Li₂MnO₃纳米线。测试分析了富锂Li₂MnO₃和MnO₂纳米线作为锂离子电池电极材料及MnO₂纳米棒作为钠离子电池电极材料的电化学性能。进一步研究了纳米化和预锂化策略对电化学性能优化的机制。本文主要研究成果如下：

1、通过水热法与固相反应相结合的方法可控合成MnO₂纳米线/纳米棒，预锂化得到富锂Li₂MnO₃纳米线，提高了MnO₂的循环性能和充放电容量。并通过热重TG、XRD、SEM、EDS、TEM和BET等材料测试手段表征了所制备的产物，确定了富锂Li₂MnO₃纳米线的最佳烧结温度（650 ^oC）。

2、研究了富锂Li₂MnO₃和MnO₂纳米线作为锂离子电池负极材料的电化学性能，发现富锂Li₂MnO₃纳米线电极材料显示出优异的可逆比容量以及更好的循环使用寿命。当电流密度为500 mA g^-1时，它的可逆比容量仍然可以达到1279 mAh g^-1（第500圈）。并初步探索了LiMn₂O₄ /Li₂MnO₃全电池的应用前景。作为一种之前从未报道的锂离子电池负极材料，采用XPS和XRD进一步探究了富锂Li₂MnO₃纳米线的电化学性能优化机理。优异的电化学性能主要归因于富锂策略，一方面归功于中间过渡二价锰在充放电过程中起到电化学缓冲的作用，另一方面归功于预嵌入的锂减缓了体积变化造成的应力应变而起到物理缓冲的作用。

3、初步研究了MnO₂纳米棒作为钠离子电池电极材料的电化学性能。这表明其具有独特的电化学特性。这种材料显示有两对氧化还原峰，既可以作为正极材料又可以作为负极材料。当电流密度为100 mA g^-1时，它的首次放电容量可以达到668 mAh g^-1，8圈后其可逆容量仍达到496 mAh g^-1。

[1]Tarascon J M, Armand M. Issue and challenges facing rechargeable lithium batteries [J]. Nature, 2001, 414(6861): 359-367

[2]Kang B, Ceder G. Battery materials for ultrafast charging and discharging [J]. Nature, 2009, 458, 190-193.

[3]Kim S W, Seo D H, Ma X H, et al. Electrode materials for rechargeable sodium-Ion batteries: potential alternatives to current lithium-ion batteries [J]. Advanced Energy Materials, 2012, 2, 701-910.

[4]Ji L W, Lin Z, Alcoutlabi M, et al. Recent developments in nanostructured anode materials for rechargeable lithium-ion batteries [J]. Energy & Environmental Science, 2011, 4, 2682-2699.

[5]Arico A S, Bruce P, Scrosati B, et al. Nanostructured materials for advanced energy conversion and storage devices [J]. Nature Materials, 2005, 4, 366-376.

[6]Bruce P G, Bruno S and Tarascon J M. Nanomaterials for rechargeable lithium batteries [J]. Angewandte Chemie International Edition, 2008, 47, 2930-2946.

[7]Etacheri V, Marom R, Elazari R, et al. Challenges in the development of advanced Li-ion batteries: a review [J]. Energy & Environmental Science, 2011, 4, 3243-3262.

[8]Scrosati B, Hassoun J, Sun Y K. Lithium-ion batteries. a look into the future [J]. Energy & Environmental Science, 2011, 4, 3287-3295.

[9]Slater M D, Kim D, Lee E, et al. Sodium-ion batteries [J]. Advanced Functional Materials, 2013, 23, 947-958.

[10]Palomares V, Serras P, Villaluenga I, et al. Na-ion batteries, recent advances and present challenges to become low cost energy storage systems [J]. Energy & Environmental Science, 2012, 5, 5884-5901.

[11]Hong S Y, Kim Y, Park Y, et al. Charge carriers in rechargeable batteries: Na ions vs. Li ions [J]. Energy & Environmental Science, 2013, 6, 2067-2081.

[12]Chang L, Mai L Q, Xu X, et al. Pore-controlled synthesis of Mn2O3 microspheres for ultralong-life lithium storage electrode [J]. RSC Advances, 2013, 3, 1947-1952.

[13]Mai L Q, Dong F, Xu X, et al. Cucumber-Like V2O5/poly (3,4-ethylenedioxythiophene) &MnO2 nanowires with enhanced electrochemical cyclability [J]. Nano Letters, 2013, 13, 740?745.

[14]Dong S M, Chen X, Gu L, et al. One dimensional MnO2/titanium nitride nanotube coaxial arrays for high performance electrochemical capacitive energy storage [J]. Energy & Environmental Science, 2011, 4, 3502-3508.

[15]Iijima S. Helical microtubules of graphitic carbon [J]. Nature, 1991, 354, 56-58.

[16]张立德，牟季美. 纳米材料和纳米结构 [M]. 北京：科学出版社，2001, 124-138.

[17]Sung D Y, Kim I Y, and Kim T W, et al. Room Temperature Synthesis Routes to the 2D Nanoplates and 1D Nanowires /Nanorods of manganese oxides with highly stable pseudocapacitance behaviors [J]. The Journal of Physical Chemistry C, 2011, 115, 13171-13179.

[18]Son J H, Wei J, Cobden D, et al. Hydrothermal synthesis of monoclinic VO2 micro and nanocrystals in one step and their use in fabricating inverse opals [J]. Chemistry of Materials 2010, 22, 3043–3050.

[19]Gao L, Wang X F, Xie Z, et al. High-performance energy-storage devices based on WO3 nanowirearrays/carbon cloth integrated electrodes [J]. Journal of Materials Chemistry A, 2013, 1, 7167-7173.

[20]Ding N, Liu S, Feng X Y, et al. Hydrothermal growth and characterization of nanostructured vanadium-based oxides [J]. Crystal Growth & Design, 2009, 9, 1723-1728.

[21]Mai L Q, Hu B, Chen W, et al. Lithiated MoO3 nanobelts with greatly improved performance for lithium batteries [J]. Advanced Materials, 2007, 19, 3712-3716.

[22]Xu J J, Wang K, Zu S Z, et al. Hierarchical nanocomposites of polyaniline nanowire arrays on graphene oxide sheets with synergistic effect for energy storage [J]. ACS Nano, 2010, 4, 5019-5026.

[23]Tang C J, Wang G Z, Wang H Q, et al. Facile synthesis of Bi2S3 nanowire arrays [J]. Materials Letters, 2008, 62, 3663-3665.

[24]Lee J, Kim J, Hyeon T. Recent progress in the synthesis of porous carbon materials [J]. Advanced Materials, 2006, 18, 2073–2094.

[25]Du N, Xu Y F, Zhang H, et al. Porous ZnCo2O4 nanowires synthesis via sacrificial templates: high-performance anode materials of Li-ion batteries [J]. Inorganic Chemistry, 2011, 50, 3320–3324.

[26]Lu Q Y, Gao F, et al. Ordered SBA-15 nanorod arrays inside a porous alumina membrane [J]. Journal of the American Chemical Society, 2004, 126, 8650-8651.

[27]Tao S L, Desai T et al. A Aligned arrays of biodegradable poly(ε-caprolactone) nanowires and nanofibers by template synthesis [J]. Nano Letters, 2007, 7, 1463-1468.

[28]Molares M E T, BuschmannV et al. Single-Crystalline copper nanowires produced by electrochemical deposition in polymeric ion track membranes [J]. Advanced Materials, 2001, 13, 62-65.

[29]Tao F F, Guan M Y et al. An easy way to construct an ordered array of nickel nanotubes: the triblock-copolymer-assisted hard-template method [J]. Advanced Materials, 2006, 18, 2161- 2164.

[30]Hu C C, Chang K H et al. Design and tailoring of the nanotubular arrayed architecture of hydrous RuO2 for next generation supercapacitors [J]. Nano Letters, 2006, 6, 2690-2695.

[31]Zhu C B, Yu Y, et al. Electrospinning of highly electroactive carbon-coated single-crystalline LiFePO4 nanowires [J]. Angewandte Chemie International Edition, 2011, 50, 6278-6282.

[32]Zhang S, Li Y, et al. Li2MnSiO4/Carbon Composite Nanofibers as a High-Capacity Cathode Material for Li-Ion Batteries [J]. Soft Nanoscience Letters, 2012, 2, 54-57.

[33]Kempa T J, Day R W, et al. Semiconductor nanowires: a platform for exploring limits and concepts for nano-enabled solar cells [J]. Energy & Environmental Science, 2013, 6, 719-733.

[34]Kempa T J, Kim S K, et al. Facet-selective growth on nanowires yields multi-component nanostructures and photonic Devices [J]. Journal of the American Chemical Society, 2013, 135, 18354-18357.

[35]KimS K, Song K D et al. Design of nanowire optical cavities as efficient photon absorbers [J]. ACS Nano, 2014, 8, 3707-3714.

[36]Yaoa J, Yana H. Nanowire nanocomputer as a finite-state machine [J]. Proceedings of the national academy of sciences, 2014, 111, 2431-2435.

[37]Karni T C, Lieber C M. Nanowire nanoelectronics: Building interfaces with tissue and cells at the natural scale of biology [J]. Pure and Applied Chemistry, 2013, 85, 883-901.

[38]Qu L T, Dai L. Carbon nanotube arrays with strong shear binding-on and easy normal lifting-off [J]. Science, 2008, 322, 238-242.

[39]Wang Z L, Song J H. Piezoelectric nanogenerators based on zinc oxide nanowire arrays [J]. Science, 2006, 312, 242-245.

[40]Feng Y, Cho I S, Rao P M, et al. Sol-flame synthesis: a general strategy to decorate nanowires with metal oxide/noble metal nanoparticles [J]. Nano letters, 2012, 13, 855-860.

[41]Yan R X, Gargas D et al. Nanowire Photonics [J]. Nature Photonics, 2009, 3, 569-576.

[42]Wu H, Chan G, et al. Stable cycling of double-walled silicon nanotube battery anodes through solid-electrolyte interphase control [J]. Nature Nanothchnology, 2012, 7, 310-315.

[43]Mai L Q, Dong Y, J et al. Single nanowire electrochemical devices [J]. Nano Letters, 2010, 10, 4273-4278.

[44]Mai L Q, Yang F, et al. Hierarchical MnMoO4/CoMoO4 heterostructured nanowires with enhanced supercapacitor performance [J]. Nature Communnications, 2011, 2, 381-386.

[45]Wei Q L, An Q Y, et al. One-pot synthesized bicontinuous hierarchical Li3V2(PO4)3/C mesoporous nanowires for high-rate and ultralong-life lithium-ion batteries [J]. Nano Letters, 2014, 14, 1042?1048.

[46]Yan M Y, Wang F C, et al. Nanowire Templated Semihollow Bicontinuous Graphene Scrolls: Designed Construction, Mechanism, and Enhanced Energy Storage Performance [J]. Journal of the American Chemical Society, 2013, 135, 18176?18182.

[47]Liu J, Zhang J G, et al. Materials Science and Materials Chemistry for Large Scale Electrochemical Energy Storage: From Transportation to Electrical Grid [J]. Advanced Functional Materials, 2013, 23, 929–946.

[48]Choi D W, Wang D H et al. LiMnPO4 Nanoplate Grown via Solid-State Reaction in Molten Hydrocarbon for Li-Ion Battery Cathode [J]. Nano Letters, 2010, 10, 2799-2805.

[49]Thackeray M M, Kang S H et al. Li2MnO3-stabilized LiMO2 (M = Mn, Ni, Co) electrodes for lithium-ion batteries [J]. Journal of Materials Chemistry, 2007, 17, 3112-3125.

[50]Reddy M V, Rao G V S, Metal oxides and oxysalts as anode materials for Li ion batteries [J]. Chemical Review, 2013, 113, 5364?5457.

[51]Shen L, Yuan C, et al. Novel template-free solvothermal synthesis of mesoporous Li4Ti5O12-C microspheres for high power lithium ion batteries [J]. Journal of Materials Chemistry, 2011, 21, 14414-14416.

[52]Lee S W, McDowell M T et al. Anomalous shape changes of silicon nanopillars by electrochemical lithiation [J]. Nano Letters, 2011, 11, 3034-3039.

[53]Wu M. S, Chiang P C J, et al. Synthesis of manganese oxide Electrodes with interconnected nanowire structure as an anode material for rechargeable lithium ion batteries [J]. The Journal of Physical Chemistry B, 2005, 109, 23279-23284.

[54]Palomares V, Serras P, et al. Na-ion batteries, recent advances and present challenges to become low cost energy storage systems [J]. Energy & Environmental Science, 2012, 5, 5884-5901.

[55]Komaba S, Takei C, et al. Electrochemical intercalation activity of layered NaCrO2 vs. LiCrO2 [J]. Electrochemistry Communications, 2010, 12, 355-358.

[56]Bhide A, Hariharan K, et al. Physicochemical properties of NaxCoO2 as a cathode for solid state sodium battery [J]. Solid State Ionics, 2011, 19, 360-363.

[57]Recham N, Chotard J N et al. Ionothermal synthesis of sodium-based fluorophosphate cathode materials [J]. Journal of the Electrochemical Society, 2009, 156, 993-999.

[58]Wenzel S, Hara T, et al. Room-temperature sodium-ion batteries: Improving the rate capability of carbon anode materials by templating strategies [J]. Energy & Environmental Science, 2011, 4, 3342-3345.

[59]Senguttuvan P, Rousse G, et al. Na2Ti3O7: Lowest voltage ever reported oxide insertion electrode for sodium ion batteries [J].Chemisry of Materials, 2011, 23, 4109-4111.

[60]Sun Y, Zhao L, Pan H, et al. Direct atomic-scale confirmation of three-phase storage mechanism in Li4Ti5O12 anodes for room-temperature sodium-ion batteries [J]. Nature Communications, 2013, 4: 1870-1880.

[61]魏春光.二氧化锰的隧道调控和电化学离子存储性能研究 [D].北京：清华大学，2013.

[62]韩晓辉,张莹,刘开宇等.二氧化锰电容材料的制备及性能表征[J].电池工业, 2008, 13, 30-34.

[63]张莹,刘开宇,张伟等.二氧化锰超级电容器的电极电化学性质 [J].化学学报, 2008, 66, 909-913.

[64]Xu M W, Zhao D D, et al. Mesoporous amorphous MnO2 as electrode material for supercapacilor [J]. Journal of Solid State Electrochemistry, 2007, 11, 1101-1107.

[65]Li Q, Wang Z L, Li G R, et al. Design and synthesis of MnO2/Mn/MnO2 sandwich- structured nanotube arrays with high supercapacitive performance for electrochemical Energy Storage [J]. Nano Letters 2012, 12, 3803-3807.

[66]李英品,周晓荃,周慧静等. 纳米结构MnO2的水热合成晶型及形貌演化 [J].高等学校化学学报, 2007, 28, 1223-1226.

[67]Luo J Y, Zhang J J, Xia Y Y. Highly electrochemical reaction of lithium in the ordered mesoporosus β-MnO2 [J]. Chemistry of Materials, 2006, 18, 5618-5623.

[68]Qu Q, Zhang P, Wang B, et al. Electrochemical performance of MnO2 nanorods in neutral aqueous electrolytes as a cathode for asymmetric supercapacitors [J]. The Journal of Physical Chemistry C, 2009, 113, 14020-14027.

[69]Xiao W, Wang D, Lou X W. Shape-controlled synthesis of MnO2 nanostructures with enhanced electrocatalytic activity for oxygen reduction [J]. The Journal of Physical Chemistry C, 2009, 114, 1694-1700.

[70]Lu X, Zhai T, Zhang X, et al. WO3–x@ Au@ MnO2 Core–Shell Nanowires on Carbon Fabric for High-Performance Flexible Supercapacitors [J]. Advanced Materials, 2012, 24, 938-944.

[71]Liu J, Jiang J, Cheng C, et al. Co3O4 Nanowire@ MnO2 Ultrathin Nanosheet Core/Shell Arrays: A New Class of High-Performance Pseudocapacitive Materials [J]. Advanced Materials, 2011, 23, 2076-2081.

[72]Chen S, Zhu J, Wu X, et al. Graphene oxide-MnO2 nanocomposites for supercapacitors [J]. ACS Nano, 2010, 4, 2822-2830.

[73]Wu Z S, Ren W, Wang D W, et al. High-energy MnO2 nanowire/graphene and graphene asymmetric electrochemical capacitors [J]. ACS Nano, 2010, 4, 5835-5842.

[74]Hu L, Chen W, Xie X, et al. Symmetrical MnO2–carbon nanotube–textile nanostructures for wearable pseudocapacitors with high mass loading [J]. Acs Nano, 2011, 5, 8904-8913.

[75]Yuan L, Lu X H, Xiao X, et al. Flexible solid-state supercapacitors based on carbon nanoparticles/MnO2 nanorods hybrid structure [J]. ACS Nano, 2011, 6, 656-661.

[76]He Y, Chen W, Li X, et al. Freestanding three-dimensional graphene/MnO2 composite networks as ultralight and flexible supercapacitor electrodes [J]. ACS Nano, 2012, 7, 174-182.

[77]Peng L, Peng X, Liu B, et al. Ultrathin two-dimensional MnO2/graphene hybrid nanostructures for high-performance, flexible planar supercapacitors [J]. Nano letters, 2013, 13, 2151-2157.

[78]Liu R, Duay J, Lee S B. Redox exchange induced MnO2 nanoparticle enrichment in poly (3, 4-ethylenedioxythiophene) nanowires for electrochemical energy storage [J]. ACS Nano, 2010, 4, 4299-4307.

[79]Guo C X, Wang M, et al. A Hierarchically Nanostructured Composite of MnO2/Conjugated Polymer/Graphene for High-Performance Lithium Ion Batteries [J]. Advanced Energy Materials, 2011, 1, 736-741.

[80]Lu X, Yu M, Wang G, et al. H-TiO2@ MnO2//H-TiO2@ C Core-Shell Nanowires for High Performance and Flexible Asymmetric Supercapacitors [J]. Advanced Materials, 2013, 25, 267-272.

[81]Wu M S, Chiang P C J, Lee J T, et al. Synthesis of manganese oxide electrodes with interconnected nanowire structure as an anode material for rechargeable lithium ion batteries [J]. The Journal of Physical Chemistry B, 2005, 109, 23279-23284.

[82]Zhao J, Tao Z, Liang J, et al. Facile synthesis of nanoporous γ-MnO2 structures and their application in rechargeable Li-ion batteries [J]. Crystal Growth and Design, 2008, 8, 2799-2805.

[83]Reddy A L M, Shaijumon M M, Gowda S R, et al. Coaxial MnO2/carbon nanotube array electrodes for high-performance lithium batteries [J]. Nano Letters, 2009, 9, 1002-1006.

[84]Gu X, Chen L, Ju Z, et al. Controlled growth of porous α-Fe2O3 branches on β-MnO2 nanorods for excellent performance in lithium-ion batteries [J]. Advanced Functional Materials, 2013, 23, 4049-4056.

[85]Kundu M, Ng C C A, Petrovykh D Y, et al. Nickel foam supported mesoporous MnO 2 nanosheet arrays with superior lithium storage performance [J]. Chemical Communications, 2013, 49, 8459-8461.

[86]Hu Y Y, Liu Z, Nam K W, et al. Origin of additional capacities in metal oxide lithium-ion battery electrodes [J]. Nature Materials, 2013, 12, 1130-1136.

[87]Su D, Ahn H J, Wang G. β-MnO2 nanorods with exposed tunnel structures as high-performance cathode materials for sodium-ion batteries [J]. NPG Asia Materials 2013, DOI:10.1038/am.2013.56.