LG Chem Ltd., South Korea's leading chemicals and battery maker, said Friday its net profit soared nearly 56 percent in the second quarter from a year ago improved margins in the petrochemical business during the peak season.

Net income came at 352.9 billion won ($307.5 million) in the April-June period, a 55.6 percent hike from a year earlier, the company said in a regulatory filing.

Sales decreased 13.6 percent on-year to 5.07 trillion won, while operating profit gained 56.7 percent to 563.4 billion won, it said.

  The company said strong demand and increased sales of premium petrochemical products enhanced its profitability in the peak season.

"Despite the regular maintenance of a naphtha cracker center, a rise in average sales prices and robust sales in premium petrochemical products improved the second-quarter earnings," Chief Financial Officer Cho Seok-jae said in a briefing.

"(Ethylen-naphtha) spread is likely to remain stable in the third quarter as well on the back of strong demands and savings in raw materials."

Sales of IT and electronics parts slowed due to weak demand from major clients and the maintenance of liquid-crystal display glass facilities, while the polarizer film market division managed to expand its market share in China after expanding production in Nanjing.

Operating margins of mid- and large- sized batteries for electric vehicles suffered due to costly infrastructure investment, but the battery division is expected to reap a profit after clinching new deals with global automakers.

"The outlook for battery and LCD is not so favorable for now, but business expansion in China is somewhat relieving effects of uncertainties in the market," Cho said.

Shares of LG Chem inched down 0.19 percent to 260,000 won on the Seoul bourse, while the benchmark KOSPI lost 0.53 percent. The earnings result was released after the market close.  (Yonhap)