[en] Percolative polymer nanocomposites (PPNC) such as polymers reinforced with graphene and/or carbon nanotubes have attracted research attention on the effort to improve the energy storage capacity of polymeric materials. Such nanocomposites often associated with high energy dissipation and dielectric loss. Recently, research interests have shifted from increasing dielectric constant of PPNC to the reduction of dielectric loss associated with such nanocomposites. Various means have been employed in the suppression of energy dissipation and dielectric loss of PPNC via covalent and non-covalent modification of percolative nanofillers (PnF). For instance, chemical and mechanical (physical) techniques of insulating PnF have been employed in the reduction of current leakage, high mobility of charge carriers and direct contact of PnF in the polymer matrix. A significant reduction in the energy dissipation of PPNC has been achieved so far. However, there is still a need for further reduction of energy dissipation associated with such nanocomposites to realize their practical applications as dielectric energy storage materials. Therefore, this review summarised the various techniques employed by various studies in the reduction of energy dissipation associated with PPNC and results achieved using the techniques. The review was concluded with present challenges and the way forward to further address the challenges facing PPNC as dielectric energy storage materials.