Energy storage device, method of manufacturing same, and mobile electronic device containing same

A mobile electronic device comprising a housing, an integrated circuit die within the housing, and an energy storage device within the housing and associated with the integrated circuit die so as to be capable of providing energy to the integrated circuit die, wherein the energy storage device comprises:

• a first electrode comprising a silicon material and having a first plurality of finger portions;
• and
• a second electrode comprising the silicon material and having a second plurality of finger portions,
• wherein the first plurality of finger portions and the second plurality of finger portions are interdigitated and are separated by a trench;
• wherein the first electrode has a first sidewall facing the second electrode, the first sidewall including a first sidewall portion having a first plurality of pores and a conductive coating;
• and
• wherein the second electrode has a second sidewall facing the first electrode, the second sidewall including a second sidewall portion having a second plurality of pores and a conductive coating.

A method of manufacturing an energy storage device, the method comprising:

• providing a first silicon structure having a first plurality of finger portions and a second silicon structure having a second plurality of finger portions, the first plurality of finger portions and the second plurality of finger portions having an interdigitated configuration;
• spacing the first silicon structure from the second silicon structure by a trench positioned between the first plurality of finger portions and the second plurality of finger portions;
• etching a side surface of the first silicon structure that faces the second silicon structure to create a plurality of pores;
• etching a side surface of the second silicon structure that faces the first silicon structure to create a plurality of pores;
• and
• coating the side surfaces and the pluralities of pores of the first silicon structure and the second silicon structure with Titanium Nitride (TiN).