A lithium–sulfur (Li–S) battery is a promising
candidate
for an electrochemical energy-storage system. However, for a long
time, it suffered from the “shuttle effect” of the intermediate
products of soluble polysulfides and safety issues concerning the
combustible liquid electrolyte and lithium anode. In this work, sulfide
polyacrylonitrile (SPAN) is employed as a solid cycled cathode to
resolve the “shuttle effect” fundamentally, a gel polymer
electrolyte (GPE) based on poly(ethylene glycol) diacrylate (PEGDA)
is matched to the SPAN cathode to minimize the safety concerns, and
finally, a quasi-solid-state Li-SPAN battery is combined by an in
situ thermal polymerization strategy to improve its adaptability to
the existing battery assembly processes. The PEGDA-based GPE achieved
at 60 °C for 40 min ensures little damage to the in situ battery,
a good electrode–electrolyte interface, a high ionic conductivity
of 6.87 × 10–3 S cm–1 at
30 °C, and a wide electrochemical window of 4.53 V. Ultimately,
the as-prepared SPAN composite exerts a specific capacity of 1217.3
mAh g–1 after 250 cycles at 0.2 C with a high capacity
retention rate of 89.9%. The combination of the SPAN cathode and in
situ thermally polymerized PEGDA-based GPE provides a new inspiration
for the design of Li-SPAN batteries with both high specific energy
and high safety.