The precursor for a lithium-ion sieve is prepared using an inorganic precipitation-peptization method with titanium sulfate as the titanium source and lithium acetate as the lithium source. The effects of Ni²⁺ (Nickel ions) doping on the stability of the sol, crystal morphology and interplanar spacing of Li₂TiO₃ are investigated. The results indicate that, after Ni²⁺ doping with varying fractions, the stability of the precursor sol first increases then decreases, and the maximum stabilization time of the precursor sol doped with 1% Ni²⁺ is 87 h. When doped with 1% Ni²⁺, the sol performance is most stable, the porous Li₂TiO₃ is obtained, and the specific surface area of Li₂TiO₃ increases by up to 1.349 m²/g from 0.911 m²/g. Accompanying the increase in calcination temperature, the inhibition of Ni²⁺ doping on the growth and crystallization of grains decreases. When the temperature is lower than 750 °C, Ni atoms replace the Ti atoms that are substituted for Li atoms in the original pure Li layer, forming lattice defects, resulting in the disappearance of (002) and (−131) diffraction peaks for Li₂TiO₃, the reduced ordering of crystal structure, a decrease in the interplanar spacing of the (002) plane, lattice expansion and an increase in the particle size to 100–200 nm. When the temperature exceeds 750 °C, with the increase of calcination temperature, the influence of Ni doping on the growth and crystallinity of grains decreases, and the (002) crystal surface starts to grow again.

A microgrid (MG) is one of the most efficient ways to cope with the grid-connection of a large number of small-sized distributed energy resources. This paper presents a consensus-based fully distributed economic dispatch (ED) strategy for MGs, with the aim of tackling the difficulties of existing algorithms in modeling network power loss and providing global information. The external power grid to which the MG connects is treated as a special power source called a virtual generator, and participates in the economic dispatch process. Taking the incremental cost of a power generator as the consensus variable, a distributed ED model was formulated based on consensus protocol and a sub-gradient-based optimization method for solving this model has been proposed. The convergence of the distributed ED system was investigated by utilizing matrix spectrum radius analysis theory. The effectiveness of the proposed strategy was verified by carrying out simulation under normal operation of the MG, both with and without the consideration of network power loss. Moreover, simulation results under several scenarios, including exchanged power order variation and distributed generation plug and play, are provided to demonstrate the robustness of the distributed ED strategy.

With the increasing penetration of renewable energy in the power system, how to ensure the normal operation of urban microgrids is gradually receiving attention. It is necessary to evaluate the overall active support capability and provide optimal operation strategies for urban microgrids. The paper proposes an active–reactive power coordinated optimization method for urban microgrids with a high proportion of renewable energy. Firstly, a quantification model of the active support capability is established to evaluate the active support capacity and reactive support capacity of urban microgrids, respectively. Then, an active–reactive power collaborative optimization model, which considers multiple types of distributed resources, is established to provide optimal scheduling strategies for urban microgrids. Consequently, a platform integrating evaluation and regulation functions is constructed to enable the evaluation of the active support capability for distributed resources in urban microgrids and the scheduling of distributed resource operations. This paper aims to solve the key technical challenges of the safe operation of new urban microgrids. The simulation results demonstrate that the proposed optimal scheduling method can reduce the comprehensive operating costs of urban microgrids with high renewable energy penetration by up to 19.86% and decrease the voltage deviation rate by up to 7.25%, simultaneously improving both economic efficiency and operational security.