No, it cannot. It is a device that can supply power to devices that are normally charged via USB connection. The device can be plugged into a computer USB socket to be recharged, not to supply power to it.
If you want to extend laptop operating time, you will need some device that is made for this purpose, like the ones offered here: http://www.laptop-battery.org/Power/External-Batteries/external-laptop-battery.html or here (I use one of these): http://www.batteryspace.com/1619v4ahli-ionuniversalexternalbatteryformostoflaptop.aspx
Answers & Comments
No, it cannot.
It is a device that can supply power to devices that are normally charged via USB connection.
The device can be plugged into a computer USB socket to be recharged, not to supply power to it.
If you want to extend laptop operating time, you will need some device that is made for this purpose, like the ones offered here:
http://www.laptop-battery.org/Power/External-Batteries/external-laptop-battery.html
or here (I use one of these):
http://www.batteryspace.com/1619v4ahli-ionuniversalexternalbatteryformostoflaptop.aspx
Good luck and have a brilliant New Year :)