Synthesis And Applications Of Borate-based And Organic Conjugated Carbonyl-based Nanomaterials In Rechargeable Half/Full Batteries

Borate-based materials have broad applications because of their special physical properties ranging over nonlinear optical,electrical,ferroelectric,piezoelectric and semiconducting behaviors.But their applications for LIBs have been hindered because of the rare species,traditional single syntheses and unclear lithium storage mechanism.In recent years,sodium ion batteries（SIBs）have been viewed as a candidate alternative to LIBs because of the material abundance and standard electrode potential.But the larger radius of the Na ion than that of the Li ion also brings several problems for SIBs.It is essential to explore high-performance electrode materials for SIBs.Based on the above problems,investigations about borated-based and organic conjugated carbonyl materials have been carried out in this thesis:（1）Manganese borate hydroxide One-dimensional nanorods and corresponding manganese oxyborate nanorods as promising anodes for lithium ion batteries.A facile hydrothermal/ethanol thermal method has been developed to prepare 1D Mn₃B₇O₁₃OH nanorods and MnBO₂OH nanorod bundles using the same chemical reagents of NH₄HB₄O₇ and Mn（NO3）2.Then they were converted into Mn₂OBO₃ with corresponding morphologies via subsequent calcinations.The time-dependent experiments on the formation of Mn₃B₇O₁₃OH and MnBO₂OH were carried out,their possible formation processes might include nucleation and nanoparticle formation-aggregation and crystallization-phase evolution-oriented growth.The obtained four kinds of nanomaterials have been systematically investigated as lithium-ion battery anodes for the first time.The discharge capacities and cycle stability of w-Mn₂OBO₃ and e-Mn₂OBO₃ are better than those of the Mn₃B₇O₁₃OH and MnBO₂OH,respectively.Through an ex-situ lithiation process,the first cycle coulombic efficiency of w-Mn₂OBO₃ and e-Mn₂OBO₃ has been improved up to 77.8%and 75.3%,respectively.Based on the best performance of the w-Mn₂OBO₃,the full battery that are composed of w-Mn₂OBO₃ nanorod anode and commercial LiFePO4（or LiCoO₂）cathode was assembled for the first time to demonstrate its practical applications.（2）Mesh-like LiZnBO₃/C composites applied as a prominent stable anode for lithium ion rechargeable batteries.The LiZnBO₃/C composites were prepared through a polymer pyrolysis method.The obtained mesh-like LiZnBO₃/C displays high initial capacity(860 mAh g^-1)and excellent cycle stability(600mAh g^-1 after 400 cycles at 500 mA g^-1).Based on the ex-situ XRD and CV curves,the LiZnBO₃ undergoes an intercalation（LiZnBO₃（?）Li1+xZnBO3）-conversion（Li1+xZnBO3H Zn0（?）Zn）-alloy（Zn（?）Zn-Li）mechanism.In addition,a full cell of LiZnBO₃/C anode and excessive commercial LiCoO₂ cathode was assembled,which presented an initial reversible capacity of 658.2 mAh g^-1 at 100 mA g"1 and 603 mAh g^-1 remained after 400 cycles（average 0.02%fading in each cycle）.The excellent cycling stability of LiZnBO₃/C in LIBs may result from its special mesh-like morphology,which not only provides mesh-like lithium ion diffusion pathway but also relieves volume change during charge/discharge processes as well as avoids agglomeration of LiZnBO₃ particles with enhanced electronic conductivity.This facile route offers new insights for rational design of borate materials,and the obtained LiZnBO₃/C holds remarkable promise towards the development of energy storage electrodes.（3）Porous organic polymer/RGO composite as high performance cathode for half and full sodium ion batteries.Porous sodium salt of poly（2,5-dihydroxy-p-benzoquinonyl sulfide）/RGO（Na2PDHBQS/RGO）was synthesized and used as a novel and advanced cathode for SIlBs in ether-based electrolyte.Benefits from the effectiveness of polymerization process and the conductive improvement via introduction of RGO,it demonstrated better electrochemical performances(228,214,203,193,172 and 147 mAh g^-1 at 0.1,0.2,0.4,0.8,2 and 4C,respectively)than the individual Na2PDHBQS or RGO and the sodium salt of the monomer（disodium chloranilate,Na2CL）.The ether-based electrolyte could provide faster sodium ion and electron diffusion velocity than ester-based one.Moreover,the Na2PDHBQS/RGO has been assembled with Na2TP to compose an all-organic full cell,which delivers an initial reversible capacity of 210 mAh g^-1.The results provide novel insights in designing polymer-based cathode materials for Na-organic batteries and push forward the development of all-organic full SIBs.（4）Building and performances of all one-dimensional quinone-based organic full lithium ion battery.Firstly,one-dimensional Benzo[b]naphtho[2’,3’:5,6][1,4]dithiino[2,3-i]thianthrene-5,7,9,14,16,18-hexone（BNDTH）rods have been synthesized via a facile reflux process and investigated as a novel cathode for LIBs,which delivered improved capacity and stability by using PEDOT:PSS as binder.Then,one-dimensional sodium salt of rhein（Na₃RH,bio-derived）has been synthesized and used as advanced anodes for LIBs,which delivered a high reversible capacity of～632 mAh g^-1.Lastly,the one-dimensional quinone-based BNDTH and Na₃RH were used as cathode and anode to assemble an all-organic full battery.