LiNO_3热物性参数及热稳定性试验研究

介绍了太阳能热发电系统中的熔融盐传热蓄热介质,验证了文中试验测量方法的正确性;在此基础上完成了工业级LiNO_3盐的物性参数的测定;同时测量了经过100多个加热冷却循环后的工业级LiNO_3的热物性参数,将其与工业级LiNO_3新盐的物性参数进行比较,结果表明,在100多个加热冷却循环后工业级LiNO_3的热物性参数变化很小,热稳定性好。

Preparation and characterization of poly(lithium acrylate-arcylonitrile)/LiClO_4-LiNO_3-LiBr solid polymer electrolytes

Through orthogonal experiment, a new type of LiClO4-LiNO3-LiBr eutectic salt with optimum mole ratio of n（LiClO4）∶n（LiNO3）∶n（LiBr）=1.6∶3.8∶1.0 was prepared. The poly（lithium acrylate-acrylonitrile）/LiClO4-LiNO3-LiBr solid polymer electrolytes were prepared with poly（lithium acrylate-acrylonitrile） and （LiClO4-LiNO3-LiBr） eutectic salts. The effect of LiClO4-LiNO3-LiBr eutectic salts content on the conductivity of solid polymer electrolytes was studied by alternating current impedance method, and the structures of eutectic salts and solid polymer electrolytes were characterized by differential thermal analysis, infrared spectroscopy and X-ray diffractometry. The results show that the room temperature conductivity of LiClO4-LiNO3-LiBr eutectic salts reaches (3.11×10-4 S·cm-1.) The poly（lithium acrylate-acrylonitrile）/LiClO4-LiNO3-LiBr solid polymer electrolytes possess the highest room temperature conductivity at 70% LiClO4-LiNO3-LiBr eutectic salts content, and exhibit lower glass transition temperature of 75 ℃ compared with that of poly（lithium acrylate-acrylonitrile） of 105 ℃. A complex may be formed in the solid polymer electrolytes from the differential thermal analysis and infrared spectroscopy analysis. X-ray diffraction results show that the poly（lithium acrylate-acrylonitrile） can suppress the crystallization of eutectic salts in this system.

Synthesizing an inorganic-rich solid electrolyte interphase by tailoring solvent chemistry in carbonate electrolyte for enabling high-voltage lithium metal batteries

High-voltage(>4.0 V)lithium metal battery(LBM)is considered to be one of the most promising candidates for next-generation high-energy batteries.However,the commercial carbonate electrolyte delivers a poor compatibility with Li metal anode,and its organic dominated solid electrolyte interphase(SEI)shows a low interfacial energy and a slow Li^(+)diffusion ability.In this work,an inorganic LiF-Li_(3)N rich SEI is designed to enable high-voltage LBM by introducing nano-cubic LiF and LiNO_(3)into1 M LiPF_(6)ethylene carbonate(EC)/dimethyl carbonate(DMC)(v:v=1:1)electrolyte.Specifically,the unique nano-cubic structure of as-synthetized LiF particles achieves its high concentration dissolution in carbonate electrolyte to enhance the interfacial energy of SEI.In addition,tetramethylene sulfolane(TMS)is used as a carrier solvent to dissolve LiNO_(3)in the carbonate electrolyte,thereby deriving a Li_(3)N-rich SEI.As a result,the as-designed electrolyte shows a high average Li plating/striping CE of 98.3%after 100 cycles at 0.5 m A cm^(-2)/0.5 mA h cm^(-2).Furthermore,it also enables the ultrathin Li(~50μm)‖LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM,4.4 mA h cm^(-2))full cell to deliver a high-capacity retention of 80.4%after 100 cycles with an outstanding average CE of 99.7%.Notably,the practical application prospect of the modified electrolyte is also estimated in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)‖Li pouch cell with an energy density of 261.2 W h kg^(-1).This work sheds light on the internal mechanism of Li^(+)transport within the inorganic dominated SEI and provides a simple approach to stabilize the high-voltage LMBs.

Enhancing Li cycling coulombic efficiency while mitigating “shuttle effect” of Li-S battery through sustained release of LiNO_(3)

In practical lithium-sulfur batteries(LSBs),the shuttle effect and Li cycling coulombic efficiency(CE) are strongly affected by the physicochemical properties of solid electrolyte interphase(SEI).LiNO_(3) is widely used as an additive in electrolytes to build a high-quality SEI,but its self-sacrificial nature limits the ability to mitigate the shuttle effect and stabilize Li anode during long-term cycling.To counteract LiNO_(3) consumption during long-term cycling without using a high initial concentration,inspired by sustainedrelease drugs,we encapsulated LiNO_(3) in lithiated Nafion polymer and added an electrolyte co-solvent(1,1,2,2-tetrafluoroethylene 2,2,2-trifluoromethyl ether) with poor LiNO_(3) solubility to construct highquality and durable F-and N-rich SEI.Theoretical calculations,experiments,multiphysics simulations,and in-situ observations confirmed that the F-and N-rich SEI can modulate lithium deposition behavior and allow persistent repair of SEI during prolonged cycling.Hence,the F-and N-rich SEI improves the Li anode cycling CE to 99.63% and alleviates the shuttle effect during long-term cycling.The lithium anode with sustainable F-and N-rich SEI shows a stable Li plating/stripping over 2000 h at 1 mA cm^(-2).As expected,Li‖S full cells with this SEI achieved a long lifespan of 250 cycles,far exceeding cells with a routine SEI.The Li‖S pouch cell based on F-and N-rich SEI also can achieve a high energy density of about300 Wh kg^(-1) at initial cycles.This strategy provides a novel design for high-quality and durable SEls in LSBs and may also be extendable to other alkali metal batteries.

配位-沉淀法制备镍酸镧敏感材料

用配位-沉淀法制备了片状镍酸镧粉末，通过X射线衍射、热重-差热分析及扫描电子显微镜等实验手段对材料的结构组成及性能进行了分析表征。研究表明用该法制备LaNiO3具有方法简单、易过滤、制备时间短等特点。

Effect of Lithium Nitrate on the Structure and Property of α-Al2O3 Platelets Prepared via Solid-state Reaction

The α-Al_2O_3 platelets were prepared via solid-state reactions and the effect of the amount of lithium nitrate additive on the property of the platelets was investigated. The ICP results indicated that the high temperature calcination process resulted in a large loss of lithium species because of volatilization, but there was still a small amount of residual lithium species in the α-Al_2O_3 platelets. The SEM micrographs showed that lithium nitrate led to decrease in the thickness of α-Al_2O_3 platelets and irregular morphology of aggregates. Pore structures results exhibited that addition of lithium nitrate led to decrease in the pore size and increase in the specific surface area of aggregates of α-Al_2O_3 platelets. The XRD and IR patterns suggested that the residual lithium and aluminum oxide formed LiAl_5O_8. The existence of LiAl_5O_8 was the basic reason for the changed performance of α-Al_2O_3 platelets.

多功能界面和结构负极用于无枝晶锂金属电池

锂金属(Li)因其高比容量和低电化学电位被认为是下一代锂金属电池(LMB)负极材料的最佳选择,有望满足储能设备的要求。然而,其充放电过程中不可控的锂枝晶生长以及由此引起的循环稳定性差、库伦效率低和安全隐患高等系列问题,严重制约锂金属负极的商业化发展。本文在锂金属表面原位构筑了一层包含三维(3D)棒状微米银(Ag)的界面膜。三维棒状微米结构可均化电流密度的分布并促使电沉积锂均匀成核和生长,产生的Li-Ag合金可用于抑制“死锂”的形成,原位形成的LiNO_(3)可以增强固态电解质界面(SEI)膜的稳定性。通过结构和表面化学的协同调控作用,锂枝晶的生长被有效抑制,所获得的Li负极在10 mA/cm^(2)高电流密度下可稳定循环。本文综合考虑了实现锂均匀电沉积的多方面因素,为LMB的商业化发展提供了新见解。

Tailoring the Spatial Distribution and Content of Inorganic Nitrides in Solid-Electrolyte Interphases for the Stable Li Anode in Li-S Batteries

Among the alternatives to lithium-ion batteries,lithium-sulfur(Li-S)batteries are considered as an attractive option because of their high theoretical energy density of 2570 Wh kg^(−1).However,the application of the Li-S battery has been plagued by the rapid failure of the Li anode due to the Li dendrite growth and severe parasitic reactions between Li and lithium polysulfides.The physicochemical properties of the solid-electrolyte interphase have a profound impact on the performance of the Li anode.Herein,a lithium polyacrylic acid/lithium nitrate(LPL)-protective layer is developed to inhibit the dendrite Li growth and parasitic reactions by tailoring the spatial distribution and content of LiN_(x)O_(y) and Li_(3)N at the SEI.The modified SEI is thoroughly investigated for compositions,ion transport properties,and Li plating/stripping kinetics.Consequently,the Li-S cell with a high S loading cathode(5.0 mg cm^(−2)),LPL layer-protected thin Li anode(50μm),and 40μL electrolyte shows a long life span of 120 cycles.This work evokes the avenue for regulating the spatial distribution of inorganic nitride at the SEI to suppress the formation of Li dendrites and parasitic reactions in Li-S batteries and perhaps guiding the design of analogous battery systems.