Nitrogen-doped carbon stabilized Li Fe0.5Mn0.5PO4/rGO cathode materials for high-power Li-ion batteries

Exploring high ion/electron conductive olivine-type transition metal phosphates is of vital significance to broaden their applicability in rapid-charging devices.Herein,we report an interface engineered Li Fe0.5Mn0.5PO4/rGO@C cathode material by the synergistic effects of r GO and polydopamine-derived N-doped carbon.The well-distributed Li Fe0.5Mn0.5PO4nanoparticles are tightly anchored on r GO nanosheet benefited by the coating of N-doped carbon layer.The design of such an architecture can effectively suppress the agglomeration of nanoparticles with a shortened Li+transfer path.Meantime,the high-speed conducting network has been constructed by r GO and N-doped carbon,which exhibits the face-to-face contact with Li Fe0.5Mn0.5PO4nanoparticles,guaranteeing the rapid electron transfer.These profits endow the Li Fe0.5Mn0.5PO4/rGO@C hybrids with a fast charge-discharge ability,e.g.a high reversible capacity of 105 m Ah·g^-1at 10 C,much higher than that of the Li Fe0.5Mn0.5PO4@C nanoparticles(46 mA·h·g^-1).Furthermore,a 90.8%capacity retention can be obtained even after cycling 500 times at 2 C.This work gives a new avenue to fabricate transition metal phosphate with superior electrochemical performance for high-power Li-ion batteries.

Sustainable Lignin-Derived Carbon as Capacity-Kinetics Matched Cathode and Anode towards 4.5 V High-Performance Lithium-Ion Capacitors

The Li-ion capacitors(LICs)develop rapidly due to their double-high features of high-energy density and high-power density.However,the relative low capacity of cathode and sluggish kinetics of anode seriously impede the development of LICs.Herein,the precisely pore-engineered and heteroatomtailored defective hierarchical porous carbons(DHPCs)as large-capacity cathode and high-rate anode to construct high-performance dual-carbon LICs have been developed.The DHPCs are prepared based on triple-activation mechanisms by direct pyrolysis of sustainable lignin with urea to generate the interconnected hierarchical porous structure and plentiful heteroatominduced defects.Benefiting from these advanced merits,DHPCs show the well-matched high capacity and fast kinetics of both cathode and anode,exhibiting large capacities,superior rate capability and long-term lifespan.Both experimental and computational results demonstrate the strong synergistic effect of pore and dopants for Li storage.Consequently,the assembled dual-carbon LIC exhibits high voltage of 4.5 V,high-energy density of 208 Wh kg^(−1),ultrahigh power density of 53.4 kW kg^(−1)and almost zerodecrement cycling lifetime.Impressively,the full device with high mass loading of 9.4 mg cm^(−2)on cathode still outputs high-energy density of 187 Wh kg^(−1),demonstrative of their potential as electrode materials for high-performance electrochemical devices.

Interconnection and damping assignment and Euler-Lagrange passivity-based control of photovoltaic/battery hybrid power source for stand-alone applications

A DC hybrid power source composed of photovoltaic cells as the main power source,Li-ion battery storage as the secondary power source,and power electronic interface,is modeled based on port-controlled Hamiltonian systems and Euler-Lagrange framework.Subsequently,passivity-based controllers are synthesized.Local asymptotic stability is ensured as well.In addition,a power management system is designed to manage power flow between components.Modeling and simulation of the proposed hybrid power source is accomplished using MATLAB/Simulink.Our interest is focused on the comparison of the two passivity-based control methods and their use in hybrid power systems.

Complementary dual-doping of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)cathode enhances ion-diffusion and stability for Li-ion batteries

The Ni-richLiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered cathodes endow Li-ion batteries(LIBs)with high energy density.However,they usually suffer from limited ion-diffusion and structural instability during cycling.Although doping strategy can effectively alleviate these issues,the coupling effects of multi-element doping and the corresponding performance enhancement mechanism have been yet unclear.Here,we report a Zr/Ti dual-doped NCM811 cathode material(ZT-NCM811),in which Zr-ion is doped into both transition metal(TM)layers and lithium layers and Ti-ion is only distributed in TM layers.The dual-doping can effectively enhance crystal structure stability via inhibiting the lattice collapse along c-axis and decreasing the Li/Ni disorder.Meantime,the lattice oxygen escape is also greatly reduced due to the presence of stronger Zr-O and Ti-O bonds,further mitigating the crystal surface parasitic reactions with electrolyte.The resultant ZT-NCM811 exhibits high specific capacity of 124 m Ah/g at even 10 C,much higher than undoped and single-doped NCM811,and a retention of 98.8%at 1 C after 100 cycles.The assembled ZT-NCM811/graphite full cell also delivers superior battery performances and durability.

高比能量动力锂离子电池开发和产业化项目进展

针对“新能源汽车”试点专项“高比能量动力锂离子电池开发与产业化”的指再任务,由天津力神电池股份有限公司(以下简称力神公司)牵头嘉校、研克所、企业共16家单住合作,分别承粗了电池关键材料开发、电池单体安全研屯与妥全技术开发、电池单体开发和制造、电池糸统开发、裝车试运行等任务。项目自2016年卖施以来,开发的高比能量动力锂离子电池比能量己满足300 Wh/kg的技术指标要求,同时各项子任务均有突破性进展。