Liam Whoriskey’s lawyers will mount the argument when he attempts to overturn his conviction for the killing of Kayden McGuinness in Derry.
Senior judges listed 27-year-old Whoriskey’s appeal for hearing for this November.
Kayden was found dead in bed at his family flat in the Bogside area in September 2017.
Post-mortem examinations revealed blunt force trauma injuries, and at least 15 non-accidental bruises to his scalp.
Whoriskey, from Glenabbey Gardens in the city, was the partner of the little boy’s mother and had been looking after him on the night he died.
He denied killing the toddler, but was found guilty of manslaughter at the city’s Crown Court in October 2019.
The jury also convicted him on a second charge of child cruelty.
The following month Whoriskey was sentenced to 15 years, half to be served in prison and the rest on licence.
In court today his new legal representatives disclosed that a total of ten grounds of appeal have now been lodged.
He told judges there was also “an inadequate charge in relation to the ingredients of the offence of manslaughter”.
Referring to the prison term imposed on Whoriskey, Mr O’Donoghue further contended: “Even on conviction (he) should not have received a total sentence of 15 years.”
Fixing the appeal for a one-day hearing in November, Lady Chief Justice Dame Siobhan Keegan said: “I’m very conscious that this is a case of some vintage.’