关键词: 锂电池, 　正极材料, 　多硫代苯, 　电化学性能

Abstract: A novel orgnaosulfur cathode material named phenyl polysulfide(PPS) for lithium batteries was studied. The highly crosslinked stucture of this material with phenyl repeat units covalently linked by －Sx－moieties(x≥ 2) was designed to reduce the generation of small molecule during discharging which was one of the main reasons for its cycling capacity fade. A series of PPS with different sulfur contents were prepared through the reaction between hexachlorobenzene and Na2Sx(x ≥ 2). Galvanostatic cycling and cyclic voltammetry were used to investigate the electrochemical characteristics of this material. The results demonstrated that higher sulfur content of the material led to higher discharge capacity but more serious capacity fade during cycling. The sample PPS-10 containing 91.99％ sulfur exhibited high capacity up to 756 mAh·g－1 in the initial cycle and a stable reversible capacity 367 mAh·g－1 after 20 cycles. The discharge mechanism, the reason for capacity fade during cycling and poor coulomb efficiency of the materials were also discussed.

Key words: Lithium battery, 　Cathode material, 　Phenyl polysulfide, 　Electrochemistry performance