Hydrothermal synthesis of Li sub(2)MnSiO sub(4): Mechanism and influence of precursor concentration on electrochemical properties

The effect of the precursor concentration on the electrochemical properties of hydrothermally synthesized Li sub(2)MnSiO sub(4) is investigated. The synthesis mechanism is investigated by analyzing the chemical reaction as a function of reaction time. Results show that Li sub(2)MnSiO sub(4) is synthesized by a dissolution-recrystallization mechanism through an intermediate Mn(OH) sub(2) phase. Smaller particles produced from higher concentration precursor solution. Li sub(2)MnSiO sub(4) with smaller particle size shows larger initial discharge capacity than that of Li sub(2)MnSiO sub(4) with larger particle size which are synthesized from lower concentration precursor solution. A maximum initial charge capacity of 323 mAh g super(-1) and discharge capacity of 177 mAh g super(-1) are achieved through hydrothermal synthesis using a 2.1 M solution, while it shows serious capacity fading. Li sub(2)MnSiO sub(4) synthesized from 2.1 M solution shows 32% of capacity retention after 20 cycles. Smaller particle size of Li sub(2)MnSiO sub(4) can induce more serious side reaction with electrolyte due to its larger specific surface area, which results in structural instability during charge-discharge tests.