Abstract:

Poplar wood chips were used as raw materials, and the composites of poplar wood chip-based charcoal interlayer loaded with manganese oxide(YC/MnO) were prepared for lithium-ion battery anode by using the strongly oxidizing properties of concentrated sulfuric acid and potassium permanganate, followed by the high temperature annealing at 800 ℃. The microstructure and surface elements of YC/MnO were characterized by transmission electron microscopy, nitrogen adsorption and desorption, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical properties of the composites were analyzed by cyclic voltammetry, constant current charge-discharge and electrochemical impedance spectroscopy. The experimental results showed that the manganese oxide nanosheets were uniformly inserted between poplar wood chip-derived carbon layers, and this tightly intercalated structure effectively reduced the specific surface area(70.3 m²/g) and charge transfer resistance(87.8 Ω), increased the average pore size(3.38 nm) and ion diffusion coefficient(2.26×10^-8 cm²/s), and made this special composite structure still have a discharge specific capacity of 396.6 mAh/g at a current density of 2 A/g.When the current density was restored to 0.1 A/g, the discharge specific capacity could be restored to 696.4 mAh/g with good reversibility. The discharge specific capacity retention rates of 116.9% and 124.7% could still be maintained after 200 and 400 cycles at the current densities of 0.5 and 1.0 A/g, respectively, showing excellent cycling stability.

Key words: poplar wood, manganese oxide, lithium ion batteries, anode