Research And Design Of The Performance Of Large-Capacity Lithium-Ion Battery Materials For Energy Storage Systems

With the development of today's society and science and technology,fossil energy is becoming more and more scarce.The development of new energy has received great attention Wind power generation,hydroelectric power,photovoltaic power generation,nuclear power and other new energy generation have become an important part of distributed power generation.The load of power system is immediacy.The difference between load peak and trough is also expanding day by day.In order to meet the power demand of users,the power grid needs to face the problem of peak adjustment.Lithium-ion battery has become one of the most widely used power supply devices in the fields of consumer electronics and power units because of its high output voltage,high energy density,long cycle life,low self-discharge and low environmental pollution.The reliable safety of high energy density and high cycle efficiency lithium-ion batteries is of great significance to their wide application.In the problem of lithium battery thermal management,in addition to the use of thermal conduction to eliminate reaction heat release or environmental heat transfer.It is also possible to adjust the thermal expansion characteristics of the electrode material to adjust the stress regulation of the electrode material,reducing the risk of explosion due to the prevalence of severe heat.Materials with negative thermal expansion(NTE)characteristics can effectively reduce the stress of electrode materials.In this paper,the negative expansion materials ZrV2O7 and Zr0.1Fe0.9V1.1Mo0.9O7 materials as the electrode material of lithium-ion battery,the electrochemical properties of the lithium-ion battery were studied.(1)ZrV2O7 was prepared by solid-phase sintering method,and ZrV2O7@C were prepared by simple and fast microwave sintering method.It is found that the half-battery open-circuit voltage is related to standard electrode potential,ion diffusion and electronic conductivity.Lower resistance improves electrode performance and cycle stability,which means that the internal resistance decreases after the cycle and the electrode is in good contact.Low conductivity leads to high open-circuit voltages,but low conductivity can also lead to a decrease in battery cycle stability.The first discharge and charging capacity of the ZrV2O7 is mAhg-1 and 204 mAhg-1,respectively.The effect of carbon content on capacity is not linear,and the second discharge capacity of the ZrV2O7@C is mAhg-1,112 mAhg-1 and 140 mAhg-1,corresponding to the carbon content of 3%,5%and 9%respectively.(2)Zr0.1Fe0.9V1.1Mo0.9O7 is a near-zero thermal expansion material with potential semiconductor device applications.A promising near zero thermal expansion material with potential semiconductor device applications.We found Zr0.1Feo.9V1.1Mo0.9O7 conductivity ?=8.2×10-5,3.80×10-4,4.16×10-4,and 9.41×10-4 S/cm at 291,383,473,and 623 K,respectively.Electrical conductivity was linear for 291-413 K,and activation energy=0.160 eV,and 533-623 K,0.233 eV,indicating that Zr0.1Fe0.9V1.1Mo0.9O7 was acting as a classical doping semiconductor.Thermal excitation led to carrier concentration increase from RT-413 K led to rapid resistance decrease,high scattering probability slowed conductivity increases from 413-533 K,with intrinsic thermal excitation of semiconductor and ionic conductor materials led to rapid conductivities increases from 533-623 K.The 1st discharge and charge capacity of Zr0.1Fe0.9V1.1Mo0.9O7 and Zr0.1Fe0.9V1.1Mo0.9O7@C are 2261 mAh·g-1 and 727 mAh·g-1,the pure Zr0.1Fe0.9V1.1Mo0.9O7 material battery discharge capacity is higher than Zr0.1Fe0.9V1.1Mo0.9O7@C material battery,due to excessive carbon does not contribute capacity,resulting in a decrease in the capacity of the material.